820 A N INTROD UCTION TO ENTOMOLOG Y 



protects them. The transformations are undergone within the 

 lump of resin. After the gnats emerge the empty pupa-skins project 

 from the lump of resin as shown at the right in Figure 1038. In 

 this figure the gnat, a single wing, and a part of the antenna of each 

 sex are represented, all greatly enlarged. 



The pear-midge, Contannia pyrlvora: — The female of this species 

 deposits her eggs by means of her long ovipositor, in the interior of 

 the unopened blossoms of pear. The young fruit is destroyed by the 

 larvae. There isa single annual generation. The winter is passed in the 

 ground, usually as pup^e but sometimes as larvaj. This is an intro- 

 duced European species, which has not yet become a serious pest in 

 this countr}^ 



The chrysanthemimi gall-midge, Diarthronomyia hypogcBa. — This 

 species causes the growth of galls on the leaf, stem, and flower-head 

 of the chr^^santhemum plant, and is sometimes a serious pest in green- 

 houses. A detailed account of it is given in Bulletin No. 833 of the 

 U. S. Department of Agriculture. 



SUBSERIES B.— THE ANOMOLOUS NEMOCERA 



In this subseries the antennae are composed of many segments, 

 but are shorter than the head and thorax, and are without whorls of 

 long hairs. The segments of the flagellum of the antennae are short 

 and broad and are closely pressed together. The abdomen is com- 

 paratively stout, and the legs are shorter and stouter than in the 

 True Nemocera. 



Family BIBIONID^ 



The March-Flies 



In this family the abdomen is often comparatively robust, and 

 the legs shorter and stouter than in most of the families with thread- 

 like antennas (Fig. 1039). The antennee are rarely longer than the 

 head and thorax, and composed of short, broad, and closely-pressed- 

 together segments (Fig. 1040). These insects resemble the fungus- 

 gnats in having ocelli; but they differ from them in the shortness of 



the antennae, in the fact that the 

 coxae are not greatly elongate, 

 and that tibial spurs of an}'^ 

 magnitude are confined to the 

 front tibiae. The venation of the 

 W^^ lOAo— An ^^"SS of the typical genus is 

 V{^. lo^c).— Bihio. tlnnaotkbio representedby Figure 1041. The 



cross-vein m-cu is present, and 

 vein Cu forks at a considerable distance from the base of the wing. 

 The adult flies are generally black and red, sometimes yellow. 

 They are most common in early spring; which has suggested the name 

 March-flies; but some occur later in the season, and even in the au- 

 tumn. 



