NEMATOCERA. 



4t 



under the microscope, and impossible to count them. Only a rough 

 sketch of the balancer is therefore given here, the bulb being the 

 part which joins the body, and some groups and rows of vesicles 

 being indicated in the narrower part. 



The males are smaller than J , and their abdomens have knotty 

 pincers (Fig. 8) ; the females have pointed projecting ovipositors. 



Fig. S-- J GeiiiUi'ia of a Cecid. 



Larvce, fourteen-nnged, become pupas within the larva skin, or 

 are uncovered.* 



These characters are sufficient to separate the Cecidomyidae. 

 The limits, however, between this family or "gall gnats," as they are 

 popularly called, and the " Fungus gnats," or Mycetophilida:, cannot 

 be easily fixed, the genus Zygoneura, for instance, bridging over the 

 two families, this genus showing combinations of characters found in 

 both families ; the coxae being far less elongated, and the spurs of 

 the tibiae far shorter than in the Mycetophilidx. Besides this, they 

 have undoubted Cecid characters in the antennse, which are monili- 

 form with verticillate hairs, a character never found in "fungus- 



Winnertz figures larvae of C. Urtica and TremuliE (Lin. Ent.), PI. I., I and 2. 



