22 AMKRICAN NEUROPTERA. 



these are sub-boreal species. Several others are closely allied to 

 European species. Most of our geuera occur in Europe ; so it is 

 probable that our Henierobiid fauna has a common origin with the 

 European. As a whole they are more numerous in the north, both 

 in species and in specimens. A number of species favor pine trees. 



There are no secondary sexual differences, save in the genera 

 Dllar and Psectra. The male genitalia are usually more highly de- 

 veloped than in the ChrysopidsB, and in several of our large genera 

 these cliaracters are of the utmost importance in the separation of 

 species. 



The larvje are all (as far as known) predaceous, and have their 

 mouth-parts modified, as in the Chrysopidse, for the purpose of suck- 

 ing up the juices of their prey. The larval head, however, is not as 

 large, and the body tapers forwards so that they are spindle shaped. 

 The larvae of two genera (Climacia and Sisyra) are aquatic. That 

 of Sisyra was discovered by Hogg in 1839 in fresh water sponges. 

 Three years afterward Westwood described it as Branchiostoma 

 spongillce. It possesses jointed respiratory filaments attached to the 

 under side of the abdominal segments. Mr. Needham has pub- 

 lished an account of the habits and transformations of these forms 

 in Bull. No. 40, New York State Museum. The cocoons are made 

 above water, and consist of a dense inner case, surrounded by a 

 much larger loose network. The flies emerge in summer. 



I have reared Micromus posticus from the larva, which is not un- 

 common on trees, feeding on plant lice. It is naked, fusiform in 

 shape, pale brown in color, and has a large white spot on each side 

 of the mesothorax and metathorax. It spins a nearly spherical 

 cocoon of white silk, and transforms to the adult in ten days. 



The larvse of Hemerobius appear to be much less known than 

 allied forms ; I have not bred any, but a larva given me by Mr. 

 Schwarz probably belongs to this genus ; it has a broader head, a 

 shorter body than Chrysopa ; and the lateral processes of thorax are 

 very long ; this specimen was taken among fallen leaves and carried 

 the empty shells of several small mollusks. 



The European forms of this family have never been reviewed ; 

 McLachlan about 1870 published on the British species, and a few 

 years since treated of certain species of Hemerobius. A general 

 revision of the European species would be of great value to the 

 American student. 



