NEUROPTERA 



283 



solid cord of atrophied cells; the passage from the jnid-intestine to 

 the hind-intestine is thus closed. The atrophied part of the mid- 

 intestine ends in the walls of a dilation, the silk-receptacle {sr). 

 Into this receptacle empty the five Malpighian tubes, three of which 

 are attached by both ends and two of which extend posteriorly and 

 end free in the body cavity ; all are modified in their middle portions 

 for the secretion of silk; here the cells are much larger and more 

 irregular in shape than the ordinary Malpighian tubule cells, and 

 show singular, branched nuclei like those characteristic of silk-gland- 



Fig. 317. — Sagittal section of a larva of Sisyra: a, b-b', c-c', three silk-glands 

 attached at both ends; d, e, two silk-glands attached at one end; sr, silk- 

 receptacle; sp, spinneret; /, fat-bodies; br, brain; g, suboesophageal ganglion; 

 r, band of regenerative cells of the stomach ; p, point of junction of sucking 

 tubes; s, sucking pharynx ; w, muscle attachment of pharynx; 0, oesophagus. 

 (From Anthony.) 

 cells of caterpillars and other insects. That part of the hind-intestine 

 extending back from the silk-receptacle is a slender tube for the 

 greater part of its length ; but in the last three abdominal segments 

 it is enlarged, forming a reservoir for accumulated silk (sp), which 

 is spun from the anus when needed for making the cocoon. 



The pupse of Neuroptera are exarate, that is, their legs and wings 

 are free. In some cases (Chrysopa, Hemerobius, and Mantispa) the 

 pupa crawls about for a time after leaving its cocoon and before 

 changing to the adult. 



The known Neuroptera of the world represent twenty famiHes; 

 the wings of one or more members of each of these families have been 

 figured by the writer in his "The Wings of Insects." Thirteen of 

 these families are represented in North America; these can be sepa- 

 rated by the following table. 



TABLE OF THE FAMILIES OF NORTH AMERICAN NEUROPTERA 



A. Prothorax as long as or longer than the mesothorax and metathorax com- 

 bined. 

 B. Fore legs greatly enlarged and fitted for grasping, p. 289. Mantispid^ 

 BB. Fore legs not enlarged and not fitted for grasping, p. 289. Raphidiid^ 

 AA. Prothorax not as long as the mesothorax and metathorax combined. 



B. Hind wings broad at base and with the anal area folded like a fan when 



not in use. p. 284 Sialid^e 



BB.Hind wings narrow at base and not folded like a fan when closed. 



C. Wings with very few veins and covered with whitish powder, p. 307. 



Coniopterygidae 



CC. Wings with numerous veins and not covered with pow-der. 



D. Antennas gradually enlarged towards the end or filiform wJtIi a 

 terminal knob. 



