90 THE LIFE-STORY OF INSECTS [CH. 



and the 'Tussocks' (Lymantriidae). It is noteworthy 

 tliat in these short-lived insects the male is often 

 provided with elaborate sense-organs which, we may 

 believe, assist him to find a mate with as little delay 

 as possible ; the male may-fly has especially complex 

 eyes, while the feelers of the male silk-moth or eggar 

 are comb-like or feathery, the branches bearing 

 thousands of sensory hairs. A box with a captive 

 living female of one of these moths, if taken into a 

 wood haunted by the species becomes rapidly sur- 

 rounded by a swarm of would-be suitors, attracted 

 by the odour emitted from the prisoner's scent- 

 glands. 



Very exceptionally the imaginal stage may be 

 omitted from the life-story altogether. Nearly fifty 

 years ago N. Wagner (1865) made the remarkable 

 discovery that in the larvae of certain gall-midges 

 (Cecidomyidae) the ovaries might become preco- 

 ciously mature and unfertilised eggs might be de- 

 veloped into small larvae observable within the body 

 of the mother-larva; ultimately these abnormally 

 reared young break their way out. In this case 

 therefore there may be a series of larval generations, 

 neither pupa nor imago being formed. Extended 

 observations on the precocious reproductive processes 

 of these midges have lately been published by W. 

 Kahle (1908). A less extreme instance of an ab- 

 breviated life-story was made known by 0. Grimm 



