166 



PSYCHE. 



[February, 1901 



brownish yellow ; dorsal line faint and 

 obscure, scarcely darker than tlie 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 of the feet. Setae short, dark ; 

 tubercles obsolete ; skin granular. Later a 

 heavy black shade overspreads the posterior 

 two-thirds of the venter, especially pos- 

 teriorly, reaching the sides and finally the 

 dorsum of joint 13 in one larva, but leaving 

 the feet pale outwardly. Otherwise the larva 

 is uniformly brown, finely annulate, the 

 few dark brown dots obscure. Some of the 

 larvae passed another molt about Sept. 14 

 with width of head .9 mm., and the same 

 coloration ; but most hibernated in this 

 stage. They began feeding again April 30. 



Stage V. Head rounded, rather strongly 

 bilobed, ashen on the face, brown flecked, a 

 broad diffuse band on each side of the 

 median suture and a longer parallel one up 

 each lobe before the ocelli to vertex; width 

 I.I mm. Body ochraceous brown, shaded 

 with black ventrally on joints 9 to 13, feet 

 pale outwardly. Segments about 30-annu- 

 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 5 and 

 6. Tubercles minute, setae short, black. 



Stage VI. 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 of median suture ; width 1.6 mm. Seg- 

 ments about 30-annulate, cylindrical, imi- 

 form, slender, well drawn out; anal feet 

 projecting laterally, the plate broad rounded 

 at the end; shields all concolorous. Wood 

 brown, ochraceous dorsally on joints 3 to 13, 

 a diffuse red-brown dorsal line, becoming a 



bluish 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 a little oblique. 

 A diffuse, sparsely pulverulent, black stig- 

 matal and subventral shading, heaviest and 

 covering most of the venter of joints S to 10, 

 but leaving the foot of joint 10 outwardly 

 pale. A'enter sparsely black irrorate. 

 Thoracic feet pale. Spiracles black ; tuber- 

 cles and setae minute. 



Larvae handed me by Mr. W. D. 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 Avild cherry and 

 apple. 



Food of larvae of Simulium and Bleph- 

 AROCERA. — In making sections of the larvae 

 of Simulium and Blepharocera, in a study 

 of the post embryonic development of these 

 flies, I have found a peculiar obstacle in the 

 presence in the alimentary canal of hundreds 

 of the tiny silicious shells of diatoms. From 

 an examination 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 clinging to the smooth rock beds 

 of swiftly flowing streams. I have men- 

 tioned, in a paper in the Entomological News 

 (January, 1900) the curious fact that the fully 

 grown larvae of Blepkaroceya capitaia are 

 covered dorsally with a close growth of dia- 

 toms. The most abundant diatoin in this 

 growth was one of the stalked Gomphonema. 

 The basis of this covering of the larva's back 

 was the gelatinous mass at the base of the 

 stalked diatoms. Scattered upon and through 

 this mass were individuals of Nitzschia and 

 several other diatomaceous 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- 



