226 TRUE TALES OF THE INSECTS. 



retracted head and thorax short and broad, and antennae 

 slightly pectinated in the males ; insects often exceed- 

 ingly richly coloured. In their maxillae, or proboscis, 

 they offer a striking contrast to the Sphinginae. It is 

 short or wanting, and of course, minus a tongue, the 

 moths are incapable of feeding. They are heavy and 

 sluggish in motion ; the wings are not built for rapid or 

 sustained flight, consequent upon the poorly developed 

 state of the thoracic muscles. But they fly to light, and 

 in this way many are taken. Withal they are truly 

 Sphingiform in larval and imaginal characters, and have 

 the anal horn, but the insects are thoroughly bombici- 

 form in habit and appearance (see Fig. 42). 



One of the distinguishing characters of the Sphingidae, 

 the reader is aware, is their smooth, hairless larvae. 

 Strange to say, it is a received opinion that they are an 

 outgrowth of a spinous or bristly haired larval group, the 

 posterior spine, or caudal horn, of Sphingidae being 

 regarded as a remnant of a general spinous covering. 

 Probably the horn is developed from one or more spines 

 or bristles, the skin itself at the base of which has been 

 prolonged, and stiffened by chitine. 



In form and structure the Sphingidae seem to be 

 most closely related to the American group of the 

 Ceratocampinae. If we regard the larvae of the latter, 

 we see the anal horn become stouter and more developed 

 through the series Dryocampa, Anisota, Citheronia ; the 



