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Psyche 3:27-43, 1880.

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RECENT STUDIES IN INSECT ANATOMY.
THIRD ANNUAL ADDRESS OF THE PRESIDENT.
In the annual address expected from the
chair of the Cambridge Entomological club, your first President discussed the then re- cent contributions to our knowledge of the life-history of insects, and last year some of the phenomena of their geographical dis- tribution were brought to your notice ; a third side of entomological study fortu- nately 'enmuns for me, and so - simply
as a recorder, not as a critic - I will en- deavor to lay before you tonight a brief re- view of the works relating to insect anat- omy and physiology which have been pub-
lished during the past two years. As this could not have been attempted, without
the aid of Prof. Carus' Zoologischer An- zeiger, let me join in the paean which
grateful zoologists raise to the editor and publisher of this invaluable record of zo- ological progress.'
We find very few general works, as one
may suppose, to be noticed.
The conclud-
ing part of Dr. Graber's useful manual
1 After much of this address was written, the record by Mr. Frank Crisp in the Monthly Journ. Royal Micros. Society came to my notice, and proved useful, as will be seen, in many cases. 2 Les Abeilles, organs et functions,etc. Paris, Baillibre, Dec. 1878.
288 p., 1 pi., 30 figs.
"Die Insecten," has just appeared. It
contains the chapters on embryology and
development, and as the first general sketch of the subject, its publication is certainly epoch-making. Mr. Emerton's " Struc-
ture and Habits of Spiders " contains much on the anat6my and development of thrse
animals, and, with its numerous original figures, will be of great service to general students.
Mr. Maurice Girard2 has published a
work on bees, which I have not yet seen. And this is also the case with Dr. H. Gren- acher's large work on the structure of the arthopod eye.a
The first annual report of the IT. S. En- tomological Comn~ission contains a general sketch of the anatomy of Caloptenus, by
Dr. Packard, the most important part of
which is the description of the respiratory system, with its tracheae and air-sac?.
There is also a section4 on the histology of the digestive tract, by Dr. C. S. Minot. Previously unnoticed structures, in the shape 8 Untersuch. u. d. Sehorgan der Arthropoden. GOttingen, 1879.
4 See also Dr. Minot's article, Amer. Nat., (June 1878,) v. 12, p. 339.
Pu&e 3 027-43 (pre. 1903) hfp //psyche aitclub org/OT.0027 htd



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28 PSYCHE.
of twelve longitudinal, forward projecting, Mr. S. Sograff sums up hie studies on
folds on the border between the stomach certain Chitopods in a short note in Cams' and ileum, are described.
Zool. Anzeiger (v. 2, p. 16). Among the
Of the papers on the general anatomy points referred to may be mentioned the of groups or species, is one of considerable following : The tracheae resemble those
length by Dr. Ernst Voges," on the Juli- of lepidopterous larvae, and are provided dae, the greater part being a description with a simple, though very peculiar atig- of species, particularly, however, in respect matic closing apparatus. The brain con- to the male genital armature. There is sists of fibres and of cells of two sorts, the also a general description of the dermal smaller of which recall those of hexapods. skeleton, with its muscles, of the tracheal The form of the brain depends mi the system, and of the scent glands ; the sec- number of eyes and length of body. The
tion on the tracheal system being the most longer a chilopod is, the fewer eyes, and important. Voges regards the mouths of the smaller optic lobes, consequently. The the tracheae in the " stigmatic pouches," latter are totally wanting in Himantarium. as the morphological stigmata ; the pouches The structure of the eye closely approaches themselves being simple infoldings of the that of larval insects. The ovaries are
derm, carrying the true stigmata within much like those of spiders ; the nearly ripe the body. The scent glands are retorts eggs are clothed with small, probably epi- shaped bodies, the necks of which open, thelial, cells. The receptaculum seminia of course, into " foramina repugnatoria," shows a distinct muscular and epithelial and are provided with an automatic plug, wall- The testes are filled with large, the mouth being opened by the contraction quadrangular big-nucleated, mother cells, of the muscle appended to each gland. which probably arise from the epithelium In a later note6 Dr. Voges describes the of the thin, upper part. The walls of the
tracheal system of Glomeris, which seems sperm-rese.rvoirs have an epithelial, and a to approach that of the hexapods, as there delicate reticulate muscular, layer. is no stigtafttic aac, but true stigmata Glands we very uumerous. The poison which open externally, leading into short glands consist of a stout chitinoas duct, tubes (probably modified tracheal trunks), whose walls are pierced with very many which bifurcate, their forks giving rise in chitiuous tubelets which end in pear-shaped tsirn to furcating tracheae. There is, how- glands. The whole glandular system ia ever, no tracheal anastomosis. The stig- clothed with a muscular rete, as Leydig mftta are armed against the entrance of has already shows to be the case with the impurities by an edging of numerous thorn- nervous system. like structures It should be remembered
The poison glands of centipedes have
that the tubes have points for the insertion been, however, previously described by Mr. special muscles, like the stigmatic sacs of Jules Macle~d.~ According to the latter Julus.
writer, the glad lie in the terminal joint 6Zeitschr. wiss. Zool. v. 31, p. 127.
"Bull. Acad. Roy. Belg., v. 44, no. 6.
8Cfiraa' 2001. Anzeig., T. 1, p. 381,




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of the forceps, extending into the distal recognize as a tracheate arthropod, ad
half of the basal joint.
Each gland is in which can hardly fail to throw important the shape of a long sac, in the middle of light on the whole group, is also to be which runs a chitinous excretory tube gladly recorded. Mr. F. M. Balfour has strengthened by a spiral fibre, trachea- just published a short note9 on Perinatus like. Minute perforated cylinders cover capensis. Organs, apparently to be recog- the outside of the tube, to which are at- nized aa segmental, are found " at the bases tached the veryJong glandular cells, radiat- of the feet in two lateral divisions of the ing oat from the central tube.
The gland body-cavity, shut off from the central me- is enveloped exteriorlyby a tunicapryrh, dian division by longitudinal septa of trans- which is iaflected along one side and prob- verse muscles," These consist of: a dilated ably reaches, and ia attached to, the central vesicle opening at the base of the feet ; a tube, thus making a long narrow furrow coiled @mdular tube connected with this along the gland.
The latter is remarkable and subdivided again into several minor for the want of tracheae.
The central tube divisions ; a short terminal portion opening opens very obliquely on the upper surface into the body cavity. These segmental or- of the forceps just behind the point, form- gans approach more nearly those of the ing a minute, long-oval cleft,
leech. There are besides two glandular
Mr. J. A. Ryder's papers8 on Eu'rp bodies. pawupus, though not anatomical, deserve Balfourfinds a suboesopha.goa1 gangliou, mention here as recording the discovery of and distinct ~entral g~nglionic swellings new genus of Pauropods. lkypmr~pu~ for each pair of feet. la the nervous sys- superficially differs from Pauropu8, as does tern there is, therefore, more resemblance Polydesmus from JUIUS, that is, it is a flat. to the normal articulate nerve chain than tened and obtected form. There are only has been supposed to exist. There are six actual segments, instead of ten as in traces also of a sympathetic system. Pawopus^ but like the fatter nine pairs of The organ doubtfully described by Mose- legs. Eyes are wanting.
Ryder wrongly ley as a fat body, turns out to be a glandu- (as he has since recognized) figures the lar tube, opening by a nun-glandular duct legs as terminating with two claws, instead into the mouth. This Balfour regards as of one.
The mouth parts, moreover, seem honyAogous with the salivary glands, and to me to project backwards instead of for- thus of course we find another arthropodan ward as represented by Ryder. The lar- affinity in Peripatus, vae are very odd, and apparently composed Mr. A. Croneberg gives an ab~tract lo of of only three segments.
As in Pauropus, a paper in the Russian language, on the they are hexapod.
structure of three genera of Eydroff7mida Any addition to our knowledge of that
(^Bydro~1tna, &&is, 3fesaea). The mouth
remarkable form Peripatus, which we must parts, the genital, and dipstive organs are 8 Froii. Acad. Nat. Soi. PhiU., 1879, p. 139,164. 10 carm' Zool. Anz ,, v. 1, p. 816. Croneberg has Amer. Nat., v. 18, p. 603.
also published a paper (Bull. Soe.Imp. Nat. Moa- QQuart, Journ. Micr. Sci., v. 19, p.431; also Ca. cow, 187t>, No. 2, sail, not yet come to hand, on run ' Anzeig., v. 2, p. 88.
the structure of Troin&t'di~)?i.




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30 PSYCHE.
described. The latter consist of a large length of the body. The digestive appara- stomach with a variable number of coeca, tus has in its vestibule two chitinous plates. - 5 in JVesoca, 11 in Bydrachna, 34 in In the pharynx, besides the two jaws, are Eyiais.
All these coeca communicate with eight peculiar beards, consisting of two se- each other, and arc
clothed with large, ries of divaricated barbules.- The salivary brown cells, numbers of which also occur ducts are lined with a spiral thread, as is in the stomach, and represent the liver. often the case. The chylific stomach is
The excretory organs are reduced in Ey' preceded by four ventricular glands, and drachna to a single median sac, wider ah- there are four Malpighiac tubes. The anal teriorly. In
Sesaea it divides into four glands contain a great quantity of uratea, short branches, but it is more complex in and are composed of a straight part and Eylais. The terminal portion in all tends another folded back. Besides the supra? downward and runs direct to the anus. and sub- oesophageal ganglia are two inter- There is no rectum, the stomach ending mediate ones connected by means of a pe- blindly, according to Croneberg. A sort duncle to the lateral cornmisure. The fol- of fat body is found about the digestive lowing ganglia are united. organs. There are three seta of oral glands Mr. Carl Giasler has described the in Bylais which open by a comm6n duct anatomy of the once rare Amb?ychi?acyl-
into the mouth.
indriformk, and figures parts of the ner- A paper l1 by the late Dr. Hermann Le- vous, digestive, and- reproductive systems. bed, Die Spinuen der Schweiz, Bau und No new results are to be noted. Leben, &c., I have uot been able to see, Turning BOW to special papers on the
Dr. Batelli lB baa studied the anatomy of anatomy of particular organs or systems, the larva of Bistalis tenas.
The exter- we may first notice several on the dermal nal tube of the long tail is regarded as a skeleton and its appendages, modified segment, which i3 shown by the
Led by Darwin's difficulty in reconciling presence of the lateral papillae, each with the great difference between the worker its long hair, as occurs in the other body ants and the sexual individuals, Dr. H.
segments.
The retraction of the internal Dewitz14 has studied the development of tube is by two muscles inserted at its supe- the legs, and especially of the wings in riorii ttre nity, where, there are some gi- Fmim @a. His results, together with gautic cells with large nuclei, having in some additional observations on the devel- the interior, as a product of elaboration, a opment of the wings in lopidoptera, are
long twisted filament. Connected with the best summed up by using nearly his own
two tracheae are two air sacs almost the language : bb The ant-workers, like the "Neu Denhchr. d. aUg. Schweiz. Gea, f, Ka- 18 Psyche, v, 2, p, 233.
turw., v. 28. A160 separate, by Friedlimder mid 14Zeitachr. wi~s.ZooL v. 30, Suppl.,p. 78; mup- Solm.
plementary ~ote,itt'd, v. 31, p. 25; also Sitzungsb. 12 Sot. Toscan. di Sci- Nat., Proc. Verb., Nov. Gee. Eat., Berlin, 1878, 122.
1878. Shortened from notice in Ann, Mag. Hat.-Hist., 5, v. 3, p. 04.




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males and females, possess in their young " The great difference between ant work- stages small, yet identically formed wing- ers and females is nut brought about, by buds ["imaginal discs '$1 which retrograde different treatment of the larvae or eggs by during further growth.
the mature workers, but while yet. in the " The thoracic appendages of ants make
maternal body the egg receives the imprint their first appearance in the young larva, of its future destination."
as disc-shaped thickenings of the hnoderm, Dewitz farther studied the mode of origin which divide into a core (leg or wing),
of the thoracic thorns in Mpnica, which
and an envelope, with an external opening grow directly out of the hypodermis, thus (covered, of course, by the chitin layer), behaving very differently from the IOCOMC- The envelope grows into a sac or pocket- tive appendages. A section on the difficulty shaped fold within the body cavity ; the of accounting for the inheritance of worker core or bud into the respective leg or wing. characters, which Dewiti; cannot help to Daring the transition to the pupal stage clear up, concludes this interesting paper. the sac is turned inside out, or rather the Dr. Dewitz also in a short note " records opening which existed from the first, be- a case of malformation in which five joints comes enlarged and the appendage is thrush of one of the hind legs protruded through forth .
the larval skin of an ant (ha intutaiis) "The developing leg or wingof the ant
nearly ready to pupate.
Devritz does not,
and bee casts ita skin while yet in the larval however, think that this is simply a case of stage ; so that, in respect to undergoing a incompleted moult, but believes that the leg moult, there is not the least difference be- from the first, instead of lying in the hypo- tween the postembryonal formed iippead- dermic infolded sack, grew outwards and, ages of insects with a perfect or imperfect being unable to separate the hypodorm from metamorphosis (e. g., leg and wing of the the chitinous layer, pierced the latter before ant, wing and ovipositor of the ~asahop- it became much hardened. per) ; the difference being simply that in A paper by Mr. Antone Simon, on the
insects with perfect metamorphosis the new Hautekelet der arthrogastrischen Arachni- forming appendage lies generally hidden den l6 I have not, seen. in infoldings of the hypoderm, making its Schneider, in a paper17 of nearly sixty
first, appearance outwardly during pupa- pages in length, describes the different forms tion ; while ia insects with imperfect met- of scales found on the different parts of the amorphosis, this occurs at the beginning, body and wings of the lepidoptera, Two
" Likewise the formation of the lepidop plates illustrate these forms, and adiagram terous wing, and, according to my view, ofa lepidopter, showing the character of the of the appendages of alt insects, startsfrom scales on different parts in the .RJinpalocera the hypoderiu, although perhaps the enter- and Heterocera, is also given.
ing tracheae, nerves, &c., effect the internal Mr. Joseph Beck
adds a little note to
formation of the appendage.
Ilia studies on the scales of insects.
In a
l6 Cams ' ZooL AM., v. 2, p. 18S.
17 Zeitschr. ges. Natnrwiss., v. 51, p. 1, l6 Salzbwg, Verf., 1878.
"Joani. Roy. Mice. Soc.,~. 2, p. 810.




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S2 PSrCBE.
species of Mom he has found scales show- their interior being filled with long glands ing under a 1-5 44 notes of exclamation " which each open in a pore. A long hair
like Thysacouran scales, while with a 1-10 covers each pore, and on the inside of the the real ribbed structure of the scale is tibiae these hairs form athick brush. The
evident.
It isalso stated that corrugations first abdominal segment, moreover, has be- of lepidopterous scales are invariably found neath two pockets, formed by an infolding on the under side only.
Jnat the opposite of delicate skin, the margins of which are is maintained by Dr. H. Bunmister," who also provided with long hairs. In rest the also believes that there ia DO internal mem- moth keeps the hinder tibiae in these pock- brane. The striae are due to filaments ele- ets, the long hairs on both effectually pre- vated on the inner side of the upper mem- venting the escape of the ethereal oil se- bane.
In the large scales of Castnia they creted by the tibia1 glands, which has a do not traverse the scale, but terminate free. pleasant aromatic odor. This of course The lower membrane has a different inter- recalls the scent apparatus on butterfly nal structure showing a great number of wings described by Fritz Mailer, and must emdl irregular transverse lines. serve as an attraction to the opposite sex. Haller 20 figures and describes peculiar Mr. Bruoner yoit Wattenwyl a1 has found
forma found in the terminal hair bruahes of a peculiar organ on the hind femora of the Polyxenus. These are transparent, hooked Acrididae. la the farrow on the under at the end, which has three or four slender side, into which the tibia fits, about one clubbed processes directed backwards and fourth from the base, is a small wart-
lying in the same plane.
The sides of the shaped elevation, open in the centre, where hair are barbed with forward directed there ia a aoft pad, sometimes projecting points. These hairs are surrounded with like a blunt tubercle- The raised margin shorter club shaped ones. There are also of the elevation is on the basal side beset larger double comb-like hairs, the teeth of with some delicate white hairs. The pad,
which point forwards.
which has a glandular appearance, is al- Ignorant of Hick's long since published
ways white or gray. It ia found only in
paper,= Haller 2a also describes briefly the the jumping tribes, but occurs both in sucking hairs on the tarsus of male water chirping and dumb species. ^No suggestion "beetles (.Dytiscws) ; nothing iiewis reported. as to its function is offered. Dr. Ph. Bertkau has describedB an in-
Messrs. Perezs and Jousaet De Bell-
teresting scest apparatus on the last pair of esme ^ discuss the nature of buzzing in in- legs in the male of Bepialus hecta, L. In sects. True buzzing is the sound emitted this moth the posterior tarsi are aborted, by rapid wing vibrations (exceeding 80). and the tibiae are large and club-shaped, The ham of the hawk-moths 1s simply the 19 Descr. Phys., Eepabl. Argentine, v. 6, p. 21, Hatter's Ent. Nadir,, No, 17, 333. See notice Journ. Roy. Micr. Soc., v. 2, p. 886. a Verhandl. Zo01.-Bot. Gca. Wien.
Arch. f. Natnrg., v. 44, p. !.
^Compte~ rend., v. ST.
Linn. Trans., v. 22, p. 147,383.
a Ibid., p. 635.
Arch. Natarg., v. 44, p. 87.




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menoptera and diptem are the only true structure of whose proboscis was first made buzzing insects, and according to De Eel- known by Mr. Francis Darwin, is of course leame produce two sounds, a grave and a the typical example of this power in the sharp. The latter is produced by the vibra- Jepidoptera, but Breitenbach shows that tions of the thorax.
The thoracic stigmata many other genera of butterflies and moths may be closed without destroying the hum- are armed, though less formidably, for sim- mine power, thns disproving Landois'a ilar purposes. These appendages are of theory.
course confined to the end of the proboscis, Mr. Perez " in a supplementary corn-
and are modifications of simple hair etruc- murkation does not agree with Mr. De turns, such as are found on the basal por- Bellesme in thinking that a conical move- tion, consisting of the hair itself and the meatof the thorax (whatever that may be) annular basal ridge from which .it grows. can produce a sound, because on fixing the This ring becomes lengthened into a cylin- animal with a pin the movements are very drical body, still having the terminal hair, attenuated, without the movements of the which, however, becomes much reduced - wings sad the buzzing being destroyed, or often to a simple papilla. The end of the even weakenedaw
cylinder is then amed with teeth, or its Mr. Carl Gissler describes
the repug-
sides develop ribs or platea, or sometimes =torial glands of Eleodes as two reddish- several rows of teeth.
Indeed we find a
brown, mi-bilobed pieces in the form of large number of patterns connected by a Y, extending from the base of the last, more or less mimeroum stages of develop- to the middie of the second segment, a ment, and which Breitenbaeh believes may length of about 6.5 mm.
He did not auc- furnish useful systematic characters. Every teed in recognizing the nature of the secre- step in the evolution of the simple hair to tion. the perfected barb on the proboscis of The balancers in the diptera have been Opbideres may be traced. The author
studied br Messrs.. J. De Belleam and seeks to reconcile the view that these Rob. De~voidy,~ but I have not been able structures are taste organs, by suggest- to see the paper of either.
ing that this function may belong to the Dr. W. Breitenbacha2 describes the pe- simple hairs, some of which, however, euliar appendages on the proboscis of the have been developed by natural selection lepidoptera, which he thinks enable the into boring organ^.^ insect to pierce the tissues of flowers, kc., Mr. Jules Kiinekel" has examined the for honey or other juices.
The orange- termination of the nerves in the proboscis Rev. Internat. Soc., v, 8, (791, p. 281. 83 Arch. Mikr. Anat., v. 15, p. 8, and Katter'8 a Quoted front Jowm Roy. Micr, Soc,, v. 2, p. Nachr'' '' P+ 23S'
408. mPsyche, T. 2, p. 209,
88 See also a note in Cams' Zool.Anzeig., Y. 3, Bnhnciern chez lea Ins. dip. 86 pp. Parig, P- 427,
Germar Bailliere & Cie.
s* Asaoc. Franc. Avain!. Sci. (1878),771. From Bull. ad. Ddpmt. du Nod, 2 a., v. 1, p. 217. 'notice in Journ. Roy. Micr. Soc., T. 2, p. 866.



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of diptera.
The two terminal flaps of the
proboscis represent the labial palpi. The trachea-like internal structures are not real tracheae, but simply supports of the flaps, Parallel to the large trualk of these false tracheae, is the labial nerve, which soon divides into two parts, and sends a multi- tude of ramifications to the periphery and inner surface of the flaps. The former
terminate in the marginal, well developed, hairs ; the latter in the rudimentary hairs of the inner surface, which are reduced to a minute, chitinous cylinder. The nerve
filament that goea to a hair ends in the base of the latter ; but in the rudimentary hairs the filament traversing the cylinder projects beyond. These are probably gustatory,
and the former 'kctile.
Mr. V. T. Chambers" describes the
structure of the tongue in some hymenop- tera. In the A@Sw be decides it is a
sucking organ, but not in the Andrenidae. The honey in the former passes through a hollow colorless tube open at the apex,
with a smallest diameter of 1-20th of a mil- limetre ; but in the latter this tube is imper- forate at the apex. Sir. J. D. Hyatt also discussesw the same subject, differing, how- ever, from Mr. Chambers, in believing the colorless rod to be open along the median ventral line, and applied to the ventral, instead of dorsal, internal aspect of the