NEUROPTERA. 143 



found, and although it has found a defender in Dr. 

 Hagen, who (Ent. An. 1861) pronounces the insect, 

 according to his experience, to be nearly harmless, it is 

 difficult to relinquish the suspicion that to its presence 

 may he attributed the destruction of the paste and the 

 brittle condition of the binding in books long unused. 



These insects are active in all stages, and the larvae 

 and pupae resemble each other, except in the progres- 

 sively developed wings. Some species, however, never 

 fully develope their wings, the Book-louse being one of 

 these. Others, haunting the crevices of tree-trunks, of 

 palings, walls, books, &c., acquire four large and mem- 

 branous wings, the expansion of which is sometimes 

 more than half an inch. The females of at least one 

 species are famished with a spinning apparatus in the 

 mouth, and cover their eggs with a delicate silken 

 web. 



These insects are all small, the head large in propor- 

 tion and triangular, antennae long, the eyes somewhat 

 large prominent, simple eyes three or none. The body is 

 soft, and generally short and squat; the wings, when 

 fully developed, are large, and have fewer veins than 

 those of most Neuropterous insects. 



