222 AN INTRODUCTION TO ENTOMOLOGY. 



furnished with a pterostigma. The anal space of the second pair 

 of wings is small. The third segment of the tarsi is dilated and 

 bilobed ; and the fourth is very short. The abdomen in the female 

 is furnished with a long ovipositor. The larvae differ from all other 

 Sialidae in not being aquatic ; they are found under bark. 



Those species of this genus that have no ocelli have been placed 

 by some writers in a distinct genus, Inocellia. 



Family II. HEMEROBIAD.E.* 

 (Ant-lions, Lace-winged Flies, et al.*) 



The Hemerobiadae is a family of considerable extent ; and repre- 

 sentatives of it are very common throughout our country. As a 

 rule they are delicate insects, with large, gauzy wings. These wings 

 are narrow, having no anal space ; in this respect they resemble the 

 wings of the Panorpidae. But the members of this family differ 

 from the Panorpidae in not having the mouth-parts prolonged into 

 a rostrum. The larvae ,of the Hemerobiadae are predaceous ; and 

 they are remarkable for having the mouth-parts formed for sucking. 

 They thus form an apparent exception to the characters of the order 

 Neuroptera. The form of these mouth-parts is a very unusual one. 

 It i? well shown in the larva of the Ant-lion, where these organs are 

 large enough to be easily studied. The mandibles are very long ; 

 on the ventral aspect of each there is a furrow the entire length ; 

 into this furrow the long and slender maxilla fits. In this way the 

 mandible and maxilla of each side form a tube through which the 

 blood of the prey of the insect can be drawn. 



Five sub-families are represented in our fauna. These can be 

 separated by the following table : 



TABLE OF SUB-FAMILIES OF HEMEROBIADAE. 



A. Prothorax not greatly elongated ; the three pairs of legs similar in structure. 

 B. Wings with very few veins, and covered with whitish powder. 



i. CONIOPTERYGIN.E. 



BB. Wings with numerous veins, and not covered with powder. 

 C. Antennae without terminal enlargement. 



D. Subcostal vein joined to the median before the end of the wing; the 

 principal sector parallel to the median vein and giving rise to the 

 other sectors.f (Sisyra, Polystazchotes.) 2. HEMEROBIIN^E. 



* Hemerobiadae, HemerSbius: hemera (fas pa), day; bios (/S/oS), life. 

 f For explanation of terms see Fig. 71, p. 73. 



