LIFE-HISTORY OF STYLOPS 



695 



FIG. 644. Triungulin stage 



The intestine ends of styiops chiidreni. 



there is little reason to doubt that the greatly altered and abnormally 

 fat or bloated body of the insect in these supernumerary stages is 

 the result of a continuous supply of rich pabulum, which the insect 

 can imbibe with little or no effort. 



The life-history of the Stylopidae is after the same general fashion, 

 though we do not as yet know many of the most important de- 

 tails. The females are viviparous, the young 

 hatching within the body of the parent, as 

 we once found as many as 300 of the very 

 minute triungulin larvae issuing in every 

 direction from the body of what we have 

 regarded as the female of Stylops chiidreni 

 in a stylopized Andrena caught in the last 

 of April. The larvae differ notably from 

 those of the Meloidse in the feet being bulb- 

 ous and without claws, yet it is in general 

 Campodea-like and in essential features a 

 triungulin (Fig. 644). 

 in a blind sac, as in the larvae of bees, 



and this would indicate that its food is honey. The complete 

 life-history of no Stylopid is completely known. It is probable 

 that, hatched in June from eggs fertilized in April, the larvae crawl 

 upon the bodies of bees and wasps ; finally, after a series of larval 

 stages as yet unknown, 1 penetrating within the abdomen of its host 

 before the latter hibernates, and living there through the winter. 



1 Westwood in his excellent account of this group remarks: "Hence, as well as 

 from the account given by Jurine, it is evident that the pupa of the Stylops is en- 

 closed in a distinct skin, and is also in that state enveloped by the skin of the larva, 

 contrary to the suggestion of Mr. Kelly." (Class. Insects, II. 297.) This is all we 

 know about the supernumerary larval stages. 



! 



FIG. 648. 1, Egg-pod of Caloptenus differentialis with the mouth torn open, exposing the 

 newly hatched larva of Epicauta vittata (la) eating into an egg and the passage which it made 

 through the mucous covering; natural size. 2, dorsal view of the 1st larva, or triungulin, of E. 

 vittata ; 2 a, one side of the head of same from beneath, greatly enlarged so as to show the mouth- 

 parts ; 2 6, terminal joint of maxillary palpus, showing imbrications and flattened inner surface 

 armed with stout points ; 2 c, leg, showing more plainly the tarsal spines ; 2 e, labrum ; 2 d, one of 

 the abdominal joints from above, showing stout points, stigmata, and arrangement of spinous hairs. 

 3, eggs of E. vittata, the natural size indicated at side. 4, dorsal view of the carabidoid stage of the 

 2d larva of E. vittnta : 4 a, its antenna; 4ft, its right maxilla ; 4c, its leg; 4d, side view of same, 

 showing its natural position within the locust-egg mass. 5, lateral view of the ultimate or full-grown 

 stage of the 2d larva of E. vittata : 5 a, portion of the dorsal skin, showing short setaceous hairs. 

 6, third head, or that from the scarabwidoid stage of the 2d larva of E. vittata from beneath, show- 

 ing the reduction of mouth-parts as compared with the first head (2 a) ; 6 a, antenna of same ; 66, 

 maxilla of same; 6 c, mandible of same. 7, fourth head, or that of the full-grown larva of E. vittata, 

 from above : 7 a, leg of same ; 7 b, the breast-plate or prosternal corneous piece. 8, lateral view of 

 the pseudo-pupa or coarctate larva of E. vittata, with the partially shed skin adhering behind : 8 a, 

 dorsal view of same; 86, its head, from the front; 8c, same from side; Srf, tuberculous leg; 8 e, 

 raised spiracle ; 8/, anal part of same. 9, lateral view of the true pupa of Epicauta cinerea Forst : 

 9 a, ventral view of same. 10, Epicauta vittata (letnniscata or trivittate var.). 11, Epicauta 

 cinerea Forst. (=marginata Fabr.). 12, antenna of the triungulin of Epicauta pennsylvaniea : 

 12 a, maxilla of same ; 126, labial palpus of same. 13. J Ifornia minutipennis, dorsal view: 13 a, 

 lateral view of same ; 13 6, simple claw of same ; 13 c, coarctate larva ; 13 d, leg of ultimate stage of 

 2d larva. After Riley. 



