8 4 



ENTOMOLOGY 



tera (Chrysopidae, Myrmeleonidae), and in various larvae 

 whose pupae are suspended from a silken support, as in the 



coleopterous families Coc- 

 103. cinellidae and Chrysomel- 



idse (in part) and the dip- 

 terous family Syrphidse, 

 as well as most diurnal 

 Lepidoptera. 



FIG. 104. 



Head of caterpillar of Samia cecropia. a, 

 antenna; c, clypeus; /, labrum; Ip, labial palpus; 

 m, mandible; mp, maxillary palpi; o, ocelli; s, 

 spinneret. 



The silk glands of caterpillars 

 are homologous with the true 

 salivary glands of other insects, 

 opening as usual through the hy- 

 popharynx, which is modified to 

 form a spinning organ, or spin- 

 neret (Fig. 103). The silk glands 

 of Lepidoptera are a pair of long 

 tubes, one on each side of the 

 body, but often much longer than 

 the body and consequently convo- 

 luted. Thus in the silk worm 

 (Bombyx mori) they are from 

 four to five times as long as the 

 body and in 'Telea polyphemus, 

 seven times as long. In the silk 

 worm the convoluted glandular 

 portion of each tube (Fig. 104) opens into a dilatation, or silk 

 reservoir, which in turn empties into a slender duct, and the 



Silk glands of the silk worm, 

 Bombyx mori. cd, common duct; 

 d, one of the paired ducts; g, g, 

 Filippi's glands; gl, gland proper; 

 p, thread press; r, reservoir. 





