Wasps, Bees, and Ants 



487 



Fig. 688.— The fig-insect, 

 Blostophaga grossorum, 

 male. (.After Howard; 

 much enlarged.) 



plete if there were omitted all reference to certain species of Chalcidoidea 

 which are e.\ce[)tions to the general condition of parasitism obtaining in the 

 group. A number — very small in proportion to the total number of species 

 in the superfamily — of chalcidid species feed upon plants, producing small 

 galls on the plants attacked. The wheat-joint worm, 

 Isosoma liordei, whose larva live in small swellings 

 — produced by their presence — in the stems of wheat 

 and other grains, is a familiar example of these phy- 

 tophagous Chalcidids. The most interesting species 

 of this kind, however, is the "caprifying" fig-wasp, 

 Blastophaga grossorum. There are several species 

 of chalcidid fig-insects, but the species mentioned is 

 the particular one on which depends the develop- 

 ment of the Smyrna fig — by far the best of the 

 food-figs. The male Blastophagas (Fig. 688) are 

 grotesque, wingless, nearly eyeless creatures which 

 never leave the fig in which they are bred, but the fe- 

 males (Fig. 689) are winged and fly freely about among the trees. A fig is a 

 hollow, thick, and fleshy-walled receptacle in which are situated, thickly 

 crowded over the inner surface, the minute flowers. The only entrance into 

 the receptacle (or fig) is a tiny opening at the blunt free end of the young 

 fig, and even this orifice is closely guarded by scales that nearly close it. 



The eggs are laid by the females at the base 

 of the little flowers in certain figs. The 

 hatching larva; produce little galls in which 

 they lie, feeding and developing. They 

 pupate within the galls, and the wingless 

 males when they issue do not leave the 

 interior of the fig, but crawl about over the 

 galls, puncturing those in which females 

 lie, and thrusting the tip of the abdomen 

 through the puncture and fertilizing the 

 The fertilized winged female 

 gnaws out of the galls, and leaves the 

 fig through the small opening at the 

 blunt free end. She flies among the trees seeking young figs, into which 

 she crawls, and where she lays her eggs at the bases of as many flowers as 

 possible. But it is only the wild, inedible, or "caprifigs" that serve her 

 purpose. The flowers of the cultivated Smyrna seem to offer no suitable 

 egg-laying ground and in them no eggs are laid. But as the female 

 walks anxiously about inside the fig, seeking for a suitable place, she dusts 

 all the female flowers with poUen brought on her body from the male flowers 



Fig. 689.— The fig-insect, Blastophaga fgmales 

 grossorum, female. (After Howard; 

 much enlarged.) 



