240 



BULLETIN 18 2, UNITED STATES NATIONAL MUSEUM 



hypomera sometimes feebly lobed behind the coxae; anterior coxal 

 cavities entirely open behind, confluent ; front coxae large, exserted ; 

 middle coxal cavities confluent; posterior coxae contiguous, coni- 

 cal; first and second abdominal sternites absent; seventh st^ernite of 

 male sometimes slightly emarginate and with a ctenidium along pos- 

 terior margin; eighth sternite of male emarginate. 



Figure 1. — Apical abdominal sternites of males of Lithockaris: A, L. dorsalis Erichsonj B, 

 L. secunda, new species; C, L. ochracea (Gravenhorst); D, L. sororcula Kraatz, 



Remar'ks. — This genus has been a source of difficulty for many 

 years and has been given very different status by various writers. 

 Casey separated it as a subtribe distinct from Medon and most other 

 writers have considered it to be a subgenus of Medon. In my revi- 

 sion of the Paederini (Blackwelder, 1939) I endeavored to separate 

 these two as valid genera and assigned several subgenera to each. The 

 genotype of Lithocharis is nearly cosmopolitan, but the generic char- 

 acters are not pronounced or obvious. 



I assign nine AVest Indian species to this genus, three of them 

 new. Of these, five belong in the typical subgenus, three in the sub- 

 genus Stilocharis, and one in the subgenus Ophiomedon. The sub- 

 genus Pseudomedon is apparently not represented in the West Indies. 



I have examined 653 examples of this genus from the West Indies. 

 Of these, 270 arc in the British Museum, 35 in Dr. Cameron's collec- 

 tion, 40 in the United States National Museum, and over 300 col- 

 lected by me in 1935-37. 



KEY TO WEST INDIAN SPECIES OF LITHOCHARIS « 



1. Gular sutures convcrfring posteriorly 2 



Gular sutures parallel along middle 9. lieres 



2. Labrura with a median tooth or prominence 3 



Labrum with two denticles near center 6 



3. Seventh sternite of male with a ctenidium on posterior margin 4 



Seventh sternite of male unmodified 4. volans 



"The species L. mcndacia Cameron is unknown to me, and I am unable to include it in 

 the key since the necessary characters are not mentioned in Dr. Cameron's description. It 

 is placed as No. 5 in the text. 



