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Psyche 3:51-52, 1880.

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PSYCHE.
LIFE HISTORY OF PLEOTOMUS PALLENS LEG.
BY HELEN SELINA KING, AUSTIN, TEXAS.
The habitat of this species of the sub-
tribe Lampyrini is western Texas, where
the mature form appears in May, a month
later than several species of Photinus.
Both sexes are phosphorescent, the 'å feebly so, emitting a greenish light, without rays, but sufficiently bright to betray his pres- ence; the 9 is much more brilliant, her
light being sufficient to show not only her body, but also surroundin";bjects for a
distance of several centimetres. After ovi- position this light declines, and the female, who seems to have assumed the perfect
form for the purpose alone of laying eggs, soon dies. She does not feed, and is too helpless to move far from the place of her final metamorphosis, owing to the feeble support which her disproportioned body
receives from her feet. When creeping,
as she does by spasmodic efforts, she touches objects with her palpi, and moves her head from side to side. The eggs are deposited in one or more pits, which the female makes in the soft moist earth with her abdomen. The eggs are smooth, round, pale yel-
lowish, about the size of black mustard
seed, and, as far as I am aware, not phos- phorescent. In six weeks they produce
young larvae 4 mm. long, cinereous on
dorsum, dull white on venter, and emitting light from the ventral surface of the poste- rior segment. When fully grown, the larva, except that the color is different, and the body is less depressed, is precisely similar to that of the commonest species of Pho- tinus larva found here, which is perfectly represented in figure 431 of Packard's
" Guide to the Study of Insects." It has twelve segments exclusive of the head,
which latter is composed of two flattened narrower segments, the inner one forming the neck, and both retractile within the thorax. It feeds on snails ; and sheds its larval skin at least twice, possibly oftener, before reaching maturity. Under confine- ment in a pot of earth, with snails for food, it assumes the pupa state in about seven weeks, but it may attain its growth sooner when at large. Both the larval moults and the transformation to pupa are performed by the splitting of the membrane on the
pleura through the first three segments, and its removal over the posterior end of the abdomen.
The shield of the % pupa immediately
after its liberation from the larval skin, seems to consist of two fused segments ; the three following segments are narrow, and the middle one of these has a transverse depression suggesting the fusion of two
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segments at that point.
Following these tenme short, approximate, 14-jointed, hi- are seven abdominal segments. The pec-
pectinate, usually folded so as to seem mi- tinate antennae and the wing cases are
pectinate, situated in front of the eyes and seen, and on the propygidium the phospho- parallel with anterior edge of the prothorax, rescent vesicles are visible aa clear greenish their tips recurved, color fuscotestaceous. yellow spots.
From the terminal segment Prothorax finely punctulate, sobhyaline, el- are two straight processes. The pleura,! evated at ita base ; its sides beneath em- region, antennae, and feet distinguish this bracing the neck and forming a eoliar for pupa from those of Phothus. The final the head whea the latter is protruded : it metamorphosis takes place in six days. is broader than in the ordinary species of The 9 form assumed the pupa condition
firefly, fuscotestaceous, with rosy centre one week later than the 3.
It has two in some, in others with transverse, irregu- white tubercles or small processes on the lar confluent pink spots on the posterior sides of the wingbearing segments, in& part ; the flanks beneath this part are also eating the position of the future rudiment- pink. Elytra striate, elevated at their ary ety tra. The pleural region is different base, the concave humeral region em- from that of the '&, and the parts of the bracing the sides of the abdomen, whence mouth are not sheathed separately as in the elytra slope backward to a narrow de- the 'E , but are as it were muzzled.
An- hiscent point, leaving nearly three segments tennae and eyes are not visible ; the shield visible. Wings same length as elytra, and seems to consist of two fused segments, aa smoke color. Feet feeble and compressed, seen through the thin membrane. There same color as the body. Seven ventral are seven abdominal segments.
The whole segments short, the last. one pointed and body is of a salmon color.
This pupa ma- partly retracted within the penultimate, tares in six days and perfects as an apter- which is emarginate. cue imago with rudimentary elytra.
On the laat abdominal ring there is a
Thus we find that under artificial man- spot on the anterior, outer margin of dor- agement the eggs will mature sufficiently sum and venter, seen in the day as of a
to hatch in five weeks, the larva requires deeper yellow than the surrounding parts. about seven weeks to reach the pupa stage, Through this at night comes the phosphor- and the latter lasts only six days, the I in eecence, not in flashes, but aa two oval
one instance accomplishing its cycle one spots, equally evident above and below, week sooner than the 9.
In a few days but more feeble than in any other firefly after becoming perfect, the 'å dies, and the known to me. The '& has the same quick
9, after wandering a little, lays her eggs spasmodic motion noticed in the 9. He
and dies also.
feeds sparingly on the common garden
Plwtomw pollens 'å is rare.
Head snail, probably on ita slime, being, I should covered by the prothorax.
Eyes large,
think, too feeble to be actively aggressive, dark-purplish, contiguous. Labial palpi though I have seen him cling to a snail visible at tip. Maxillary palpi small shell with much persistency, Mandibles Hot prominent, wry small. An- Pleotomus paUm 9, though apparently



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PS YCHE. 53
inorc abundant than the '&, is yet compar- atively rare. It is of a buff" or salmon color, with eleven segments, pink on their posterior margins, and overlapping. Head narrow, with projecting muzzle, but im-
perfect organs of manducat,ion. Eyes small, round, black, on sides of the head. Anten- nae shorter than thorax, approximate, sit- uated in front of the eye, pale yellow, fee- bly pectinate. Thorax with margin re-
flexed, subrugose. Adjoining the shield
are the rudimentary elytra, semicircular and very small. Feet feeble, compressed ; the body is disproportionately large, and the insect consequently moves with sudden nervous action, and pauses every few steps. Though there are no special phosphores-
cent vesicles visible through the membrane, yet it emits light from the entire ventral surface of the three posterior segments. This is very brilliant, and when less intense posteriorly, appears diffused over the body. This brilliancy continues until oviposition . This ? insect is similar to Packard's illus- tration 428, of an apterous ? from Mada- gascar, plus the aborted elytra and pectin- ate antennae.
NOTE ON NORTH AMERICAN TRYPETIDAE.
BY CHARLES ROBERT OSTEN SACKEN, HEIDELBERG, GERMANY. Among a number of diptera, collected by
Mr. J. Boll in Dallas, Texas, and purchased by me in Geneva a short time ago, there
were 25 '& and 9 specimens of a Trypeta, bearing on a label " bred from galls on
Ambrosia." The insect could be easily
identified with T. qibba Loew, and as the habits of this species were hitherto un- known, I deem it worth the while to put
Mr. Boll's observation on record.
The gall, which is likewise in the collec- tion, is an oblong swelling of the stem, probably .terminal.
The habits of the following North Amer-
ican Trypeia have been hitherto investi- gated and published (the name of the dis- coverer is in parentheses) : -
Rhagoletis pomonella. - Fruit of the apple-tree ( Walsh).
Oedaspis polita. -Gall on Solidago (0. S.). '
gibba. - Gall on Ambrosia (Boll).
Eurosta solidaginis. - Gall on SoLidago (Harris). Eutreta diana. - Gall on Artemisia tridentata (Riley).
Aspzlota alba. - Seeds of Vernonia (Riley). This is a very small number, in compari- son to that of the described N. A. Trypeta ; but the most striking circumstance in con- nection with it is that among six Trypeta, '
whose habits are known, not less than four should occur in galls, and only one in the heads of a composite flower. In Europe
the Trypeta bred from galls form an imper- ceptible minority, and most of the species are obtained from the heads of composites. Compare, for instance, the list of 60 species bred by Frauenfeld (Verh. k.-k. zoo1.-bot. Gesell. Wien, 1863, p. 221-224), among
which only three formed galls on the stem of the plant.
It would be worth while for American
entomologists to collect dry heads of com- posite plants in autumn, for the purpose of breeding Trypeta ; a large number of new species of these pretty flies would probably be obtained.
September, 1879.




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