108 



stages, when the larv» poke their heads forth from their sheltered 

 homes in search of food. The presence of the larvtB as the}' approach 

 maturity and cut the leaves of their host plants may be readily detected, 

 and at this time hand-picking is all that is necessary. 



THE FICKLE MIDGE. 



{Srhira liironstanfi Fitcli.) 



Some insect inhabitants of the greenhouse that have attracted atten- 

 tion in very recent years are the larva? or maggots of certain species 

 of midges or gnats belonging to the families Cecidomyiida? and Myce- 

 tophilida\ The larvte of three species of the former family attack 

 roses and violets, and one of them has been discussed in former pages 

 of this bulletin on account of its injuries. A large proportion of the 

 Mycetophilidai belong to Sciara, a genus of considerable extent, whose 

 larva? are believed to l)e for the most part scavengers, feeding upon 

 decaying vegetable matter of different kinds, including fungus growths, 

 whence the name of "fungus gnats" which has been applied to the 

 famil3\ Some of these larva? live in vegetable mold, under the bark 

 of trees, in putref3'ing vegetal)les, in manure, and some attack roots 

 and sprouting seeds in greenhouses, and one of these, Sckwa mco7isfrms 

 Fitch, the subject of the present paper, has recenth' been reported by 

 various persons as being quite troublesome. 



The su])ject of injuries by this species is a matter for future investi- 

 gation, as there is a possibility that it agrees with other Sciaras in 

 being a scavenger, and is, perhaps, in some cases attracted to the 

 injured plants observed from the formation of fungus and other 

 growths on them. It is to be regretted that the subject was not 

 investigated earlier. 



DESCRIPTIVE. 



The adult of this insect is a minute two-winged flv or fungus gnat. 

 Like others of the group to which they belong, these liies are exceed- 

 ingly delicate, with moderately slender bodies, long slender legs, small 

 heads, and rounded, moderately prominent eyes. The female of this 

 species is shown in the illustration (fig. 29) at e. It may readily be 

 distinguished from the male shown at a by its larger size, more robust 

 al)domen when gravid, eyes somewhat smaller in proportion to its size, 

 and particularly by the last a])dominal segments. A side view of the 

 tip of the abdomen of the female is shown at y, the maxillary palpus 

 at (', and an enlarged section of the antennaB at d. At h is shown the 

 peculiar structure of the external organs of the male. The general 

 color of the ])od3^ and legs is pale brownish yellow, with darker brown 

 thorax, and black head. The Avings are still lighter and lightly infus- 



