140 



NATURAL HISTORY OF ARTHROPODS. 



ORDER III. - - PSEUDONEUROPTERA. 



It is difficult to satisfactorily characterize by a sharp-cut definition this very elastic 

 order. The definition in Dr. Hagen's " Neuroptera " is as follows : " Mandibulate 

 insects with an incomplete metamorphosis (active pupa) ; lower lip mostly cleft ; four 

 membranaceous, reticulate wings (rarely with rudimentary wings or apterous) ; 

 antennae either subulate, and then the tarsi three- to five-articulate, or setiform, or 

 filiform, in which case the tarsi are two- to four-articulate." This is not very satis- 

 factory, as the characters given are for the most part of a superficial nature. It is 

 easier to separate the present order from the Neuroptera than from the Orthoptera, 



FIG. 205. Diplax Berenice, female. 



FiG. 20C. Diplax Berenice, male. 



or grasshoppers, etc. For example, the cleft labium is to be found in Orthoptera, and 

 though, as a rule, the Orthoptera have five-jointed tarsi, the family of Mantidse have 

 four tarsal joints. The Pseudoneuroptera are closely connected with the Orthoptera> 

 especially the cockroaches (Blattame), by the white ants (Termitidas) which in some 

 important respects very closely resemble the former. Except in the characters above 

 given we have been unable to discover in the trunk or body itself any fundamental 

 characters peculiar to the Pseudoneuroptera, and which will apply to all taken together. 

 The parts of the head, the thorax, and the abdomen, show a great lack of uniformity 

 in the different groups, as does also the structure of the wings. 



SUB-ORDER I. - - PLATYPTERA. 



These forms may readily be separated from those of the next group of equivalent 

 rank by the flattened body and by the usually broad and quadrate prothorax. The 



sub-order contains four families, all of which are repre- 

 sented in our American fauna. 



The species of the family PERLID^E are called stone- 

 flies from the fact, we suppose, that they are so abundant, 

 in the pupa state, under stones in streams, while the 

 winged insects themselves, especially ferla, are to be 

 found by anglers in such situations. In England Perla 

 bicaiidata is called the stone-fly; a small, greenish species, 

 belonging to the genus Chloroperla, is called the yel- 



FIG. 207. Perla paiiida. low-sally ; while a species of Nemoura is called the 



willow-fly ; all these per lids are considered in England 

 excellent bait for trout ; in this country they are not used for bait, and have received 



