OF WASHINGTON, VOLUME XV, 1913. 23 



The appended table has been constructed from ten specimens 

 of the above mentioned species, ranging gradually from 12 to 19 

 mm. in length, measured from the outer edge of the front to tip 

 of abdomen. These measurements probably represent the ex- 

 tremes of size in the species, although Mr. D. W. Coquillett 1 

 gives them as 13 to 17 mm. 



In the existing synoptic tables, the branch of the dichotomy 

 running out at Belvosia reads "Ocellar bristles wanting." By 

 reference to the present analysis it will be seen that these bristles 

 are present in five out of the ten specimens examined, in four of 

 them only on one side of the head, in the remaining case bisym- 

 metrically developed. When present they are directed forward, 

 not strongly developed but perfectly distinct from the surrounding 

 hairs with an ordinary hand lens. 



In Mr. Coquillett's table of the genera, dichotomy 116, one 

 branch of which runs to Belvosia we read "Second segment of 

 abdomen never bearing more than four marginal macrochsetae." 

 By the present analysis we see that they may vary from 2 to 

 6 and are asymmetrically placed in two out of ten cases. 



Mr. Coquillett further says "Our species (of Belvosia) have 

 four post sutural (dorso central) and four sterno pleural macro- 

 chaeta?." It will be seen that this occurs in only one-half the 

 specimens examined. The fact is these macrochaeta? are wofully 

 variable in number, size and arrangement. 2 



A glance at our table shows that the marginal macrochaeta? of 

 the scutellum increase in number almost directly as the length and 

 robustness of the body, in fact generally speaking the larger,, 

 stouter, and therefor more fully developed the specimen, the more 

 numerous the macrochseta? become on all parts of the thorax. 



Mr. C. H. T. Townsend 3 has said: "It has been alleged that 

 much of the sg-called synonymy in this superfamily, as it stance 

 in the Aldrich Catalogue, is due to a misguided erection of species 

 on stunted specimens developed from underfed larva?, through 

 a lack of acquaintance with the breeding habits of the species. 

 It is well known to all students of the Muscoidea that the females 

 sometimes, if not frequently, carry the act of oviposit ion to an 

 extreme, ovipositing upon larva? that are already overstocked with 



1 Revision of N. A. Tachinidae, p. 84. 



2 The author wishes to disclaim most emphatically any intention or 

 attempt to discredit this admirable and indispensable paper of Mr. D. W . 

 Coquillett's. It is a pioneer work and necessarily not perfection. Mr. 

 Coquillett was fully aware of the fact, and had he lived to complete his 

 life work, it is altogether probable that a perfected revision of his paper 

 which he contemplated would have eliminated any fault in the content of 

 the original work. 



3 The Taxonomy of the Muscoidean Flies, Smithsonian Misc. Col. No. 

 1803, p. 19. 



