232 NEW YORK STATE MUSEUM 



figure 3). The claws are invariably simple and the ptil villi usually 

 as long or a little longer than the claws. 



Fig. 53 R h o p a 1 o m y i a sp. ; lateral view of abdomen showing the extensile 

 ovipositor, enlarged (original) 



Species of Rhopalomyia show a marked preference for flower or 

 bud galls, a very large proportion inhabiting deformed buds, among 

 which may be classed the conspicuous apical rosette galls, the smaller 

 flower or bud galls and reduced flower heads. A number also breed 

 in leaf galls, such for example, as R. pedicellata and 

 R. fusiformis, both of which inhabit a very characteristic 

 type of gall which may appear on the stem, the leaf or in the flower 

 head. It would appear that even this might originate while the 

 tissues were in the bud and therefore most susceptible to injury. 

 The well-known Rhopalomyia hirtipes produces a very 

 characteristic gall at the apex of aerial or subterranean stems, the 

 former being well laiown and the latter a recent discovery; both are 

 in reality bud galls. 



American members of this genus display a marked preference for 

 Solidago, some sixteen species having been reared therefrom, while 

 the closely allied aster supports four additional forms. Each species 

 of this genus producing a gall on Solidago makes a characteristic 

 deformity which appears to be correlated with marked structural 

 differences in the adult and presumably by variations in habits. 



Key to species 



a Antennae with 20 or more segments 



b 24 to 25 antennal segments; abdomen dark reddish brown; palpi biarticulate ; 

 female; reared from loose, rosette gaUs on Solidago canadensis 



Carolina Felt, C. a 1635 

 bb 22 to 23 antennal segments 



c Abdomen dark brown; legs dark brown; antennal stem one-fourth longer 

 than the basal enlargement; palpi biarticulate; male 



major Felt, C. 90 



II 



