812 



AN INTRODUCTION TO ENTOMOLOGY 



series of papers he published a synopsis of the species of North Amer- 

 ica, including the Sciarinas (Johannsen '09-' 12). 



The larvas_ of most species live upon and destroy mushrooms, 

 usually the wild plants, but sometimes they are pests in mushroom 



cellars; other species are found in 

 decaying wood; and certain species of 

 the subfamily Sciarinas are sometimes 

 pests of cultivated plants, destroying 

 seed corn, seed potatoes, and the roots 

 of other plants. 



In this family the larva is more or 

 less cylindrical, smooth, soft, whitish in 

 color, and with a small strongly chiti- 

 nized head, which is usually brown or 

 black, and is provided with mandibles 

 and maxillae. There are usually eight 

 pairs of spiracles. 



The pupa is not enclosed in the skin 

 of the larva; but in some genera the 

 transformations are undergone in a 

 delicate cocoon. 



The subfamily SciarincB.— The 

 family Mycetophilidse is divided into 

 nine subfamilies, eight of which are 

 One of these subfamilies, the Sciarinse, 

 merits special mention in this place. The members of this subfamily 

 differ from the more typical fungus-gnats as follows ; the coxas are not 

 so greatly elongated ; the eyes differ in shape, there being a narrow ex- 



Pig. 1029. — Eyes of Sciara. 

 represented in our fauna. 



A/.+2 



Fig. 1030. — Wing of Sciara. (After Enderlein.) 



pansion of each eye extending above the base of the antennas and 

 meeting or nearly meeting the expansion of the other eye, (Fig. 1029), 

 while in other fungus-gnats the eyes are either round, oval, or kidney- 

 shaped, but not markedly narrowed above; and the cross- vein r-m is 

 in the same right line with the second section of the radial sector (Fig. 

 1030). 



