Article beginning on page 165.
Psyche 9:165, 1900.

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Febwary, 19011 PSYCHE. 165
LIFE HISTORIES OF NORTH AMERICAN GEOMETRIDAE. -XIX. BY HARRISON G. DYAR, WASHINGTON, D. C.
Seuslys ennucienia GLI~II.
The larva given
by Guende as that of this species does not agree at all with observations. On the
other
hand, the one described by Goodell
does agree well. As it seemed possible that there had been some mixture of species, 1 applied to Dr. Hulst, who states that he thinks the two forms of the moth probably distinct, as follows : -
I.
Wings sordid white with faint hrown-
ish lines-
IISSNUCLBATA Gneu., Plial. I, 50.5 ; 1857. =w&trictata Walk. C. B. M. xxii, 722;
1861 = mensiwata Walk. C. B. M xxxv,
1621 ; 1866.
2. Wings with a more or less extensive
blackish submarginal powdering -
AI.ABASTARIA Hiibn. Zutr. ii, 22, fig.
31 I, 312. = eiwurleata var. Gnen. l'hal. pi. 12, fig. 3. = ennncleafa Pack (nec
Gum.) Mon. 34.7, p!. 10, fig. 67. =re-
coiidilaria Walk. C. Q. M. xxii, 786,
1861.
The moths bred from the larvae here de-
scribed were of the form ennucleata as df fined.
Egg;
Laid loosely, rolled about in the
tumbler. Roundedly elliptical, one diam- eter less than the other, but without llatten- ed areas,
slightly more sharply rounded at
the tnieropylar end; about 15 longitudinal, strongly
prominent ribs with fine parallel
cross-striae, slightly raised both across the ribs and in the interspaces. Ends confused reticulate, the ribs abruptly ending at the edge of the micropylar end, becoming
merged in the reticulations at the other. Very pale green, almost white, not shining. Sine .55 X .4 X .35 mm. (Eggs from Wash- ington, 1). C.)
Stage I.
Long, slender, thread-like, ac-
tively looping.
Head and cervical shield
pale translucent reddish brown, the head round, slightly hilobed, ocelli black; width about .3 mm. Body dark brown above and
below ; the sides broadly translucent green. ish. Thoracic feet pale, abdominal ones
dark. Setae short and stiff, black, with swollen clearer tips. Later the suhventral brown breaks up into a series of subventral streaks. The larvae remain long and
slender.
Stags II. Head round, flattened before,
not bilobed; width .4 rom. Body slender, the thorax short; smooth; ground color
translucent sordid whitish, thorax with fine dark brown snbdorsal line and a broader
subventral one ; abdomen with broad dorsal brown band tapering to a point on joint 13, leaving the sides and feet pale; a moderately broad subventral band, broken posteriorly. Stage III.
Head round, wider than high,
antennae prominent ; pale brown, dotted, a white streak on the face of each lobe edged with darker brown dots; width .G mm.
Body long and slender, cylindrical, smooth. Somewhat sordid green ; thorax with a fine dorsal line which joins the broad abdominal dorsal band, reaching joint 3, contracted slightly at the incffiiires ; a series of small round eegmental spots siibventrally, a line on the anterior edge of tlic foot of joint 10 and bases of thoracic feet dark purple brown. Setae short and stiff, dark. Skin finery transversely creased.
Anal feet long, green.
Tubercle i of head and angles of cervicnl shield a little prominent.
Sfag-e IV. Head rounded, squarish, dull
yellowish, speckled with brown; a bright shade, edged with brown without, on the
face of each lobe; width .75 mm. Body
very long and slender, finely annulated. dull



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166 PSYCHE. [February, 1901
brownish yellow; dorsal line faint and
obscure, scarcely darker than the ground except dorsally on joints 10 to 13,
where it is dark and distinct, its border marked by dark dots intersegmentally
(approximate), and centrally on the segments (remote). Thorax darkly shaded, the lines obsolescent. Venter a shade paler with
series of subventral brown dashes edging the bases oå the feet. Setae short, dark; tubercles obsolete; skin granular. Later a heavy black shade overspreads the posl.erior two-thirds of the venter, especially pos- teriorly, reaching' the sides and finally the dorsurn of joint 13 in one larva, hut leaving the feet. pale outwardly. Otherwise the larva is uniformly brown, finely annulate, the few dark brown dots obscure. Snme of the larvae passed another iTiolt about Sept. 14 with width of head .g mm., and the same
coloration ; but most hibernated in this stage.
They began fceding again April 30.
Slaye V. Head rounded, rather strongly
bilobed, ashen on the face, brown flecked, a bi-oad diffuse band on each side of the
median suture and a longer parallel one up each lobe before the ocelli to vertex ; -width 1.1 ram. Body ochraceous brown, shaded
whh black ventrally on joints y to 13, feet pale outwardly. Segments about pannu-
late. Traces of brown dorsal and subdorsal lines and black flecks near the incisures; also blackish shaded laterally posteriorly on the segments. Spiracles black; vi on a low
rounded lump, most distinct on joints ,j :md 6. Tubercles minute, setae short, black. Stage VT. Head somewhat squarely
rounded, free; whitish gray, mottled with brown, a broad, diffuse, mottled dark stripe from behind ocelli and a shorter one each side ol median suture ; width 1.6 mm. Sez- ments about 30-annulate, cylindrical, uni- Form, slender, well drawn out, anal feet projecting' laterally, the plate broad rounded at the end ; shields all concolorou's. Wood brown; ochraceons dorsally on joints 3 to 13, a diffuse red-brown dorsal line. becoming a Olnisl~ white bar on the large first annulet. Black crinkly addorsal dashes anteriorly and posteriorly on each segment, the posterior ones a little more lateral and fi little oblique. A dittiise, sparsely pulverulent, black stig- matal and s~ibventral shading, heaviest and covering most of the venter of joints 8 to 10, but leaving the foot of joint 10 outwardly pale. Venter sparsely black irrorate.
Thoracic feet pale. Spiracles black ; tuber- cles and setae minute.
Liwvae handed me by Mr. W. 11. Kearfott
from his collecting box, where they had
hatched in July; moth the following June. Single brooded, hibernation in Stage IV. The larvae were raised on wild cherry and apple.
FOOD OF LARVAE 01: SIMULIUJM AXD BLEPH-
AROCERA.-In making sections of the larvae of Sinn-ilium and Blepharocera, in a study of the post embryonic development of these llies, I have found a peculiar obstacle in the presence in the alimcnt~i.ry canal of hundreds of the tiny silicious shells of diatoms. From ;in examinaiion of the alimentary canal of many specimens of Simulium and Blepharo- cera it is apparent that diatoms constitute a large part of the food of these larvae, both of which live clinginz to the smooth rock beds of swiftly flowing streams. I have men-
tioned, ins. paper in the Entomological News (January, 1900) the curious fact that the fully grown larvae of Blephnrocera capitate, are covered dorsally wit11 a close grou-th of dia- toms. The most abundant diatom in this
growth was one of the'stalked Gomphonema. Tile basis of this covering of the larva's hack was the gelatinon? mass at the base of the stalked diatoms. Scattered upon and through this mass were individuals of Nitzschia and several other diiitoinaceo~ls genera. The cov- ering had a soft, felt-like appearance, gray- ish or brownish, and did not seem to trouble the larva. I have found a similar diatoma- ceous growth on the larvae of Liponeura and two other Blepharocerid species in Cali-



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