TAXONOMY OF MUSCOIDEAN FLIES — TOWNSEND 119 



ter in question can not be used here for the erection of a separate 

 genus. This is only another illustration of the fact that a character 

 of value for the separation of certain forms may be valueless for this 

 purpose in certain other forms closely allied to the first. In all the 

 species there'are several widely divergent pairs of weak ocellar hairs 

 behind the first or regular pair of ocellar bristles. In the forms 

 which have a second pair of ocellar bristles well developed, this sec- 

 ond pair is always inserted just behind the two posterior ocelli, and 

 not inside the ocellar triangle. In other words, it is only the pair of 

 hairs inserted just behind the two posterior ocelli that ever develop 

 into a second strong pair of bristles. L. ccesar is typical of the forms 

 in which this pair of hairs is not developed in either sex, but it is to 

 be noted that some of the bristly hairs within the ocellar triangle in 

 this species often seem strong enough to be considered additional 

 pairs of ocellar bristles. 



Fourteen species of Lucilia are here recognized, occurring in ma- 

 terial in U. S. N.. M. They may be separated as follows: 



Table of Lucilia spp. 



1. Only one postacrostichal bristle present morrilli, sp. nov. 



Two postacrostichal bristles present 7 



Three postacrostichal bristles present 2 



2. Palpi more or less yellowish 4 



Palpi wholly black or blackish 3 



3. Second pair of ocellar bristles developed sylva/rum 



Second pair not developed nigripalpis, sp. nov. 



4. Palpi wholly yellow 5 



Palpi infuscate at tip 6 



5. Second pair ocellar bristles developed sericata 



Second pair not developed angustifrons, sp. new 



6. Second pair developed giranilti, sp. n v. 



Second pair not developed barberi, sp. nov. 



7. Abdomen nnicolorous 8 



Ba^al segment of abdomen black or blackish 9 



8. Second pair developed unicolor, sp. nov. 



Second pair not developed ccesar 



9. Whole body purplish, except basal abdominal segment, second abdom- 



inal segment with a marginal row cf bristles purpurea, sp. nov. 



Whole body not so 10 



10. Second and third abdominal segments with a purplish or blackish 



margin 1 1 



Second and third segments unicolorous 12 



11. Buccse yellow wholly or partly pilatei 



Bucoe black, not at all yellow austral is, sp. nov. 



12. Eyes normal, face black infuscata, sp. nov. 



Eyes flattened anteriorly with large front aspect, face brownish yellow. 



oculata, sp. nov. 



