36 
Psyche 
[March-June 
Geographic Distribution : — I have seen this species from the fol- 
lowing localities; abbreviations are USNM: United States National 
Museum; MCZ: Museum of Comparative Zoology, Harvard Uni- 
versity; and TCB: my private collection. 
Alabama: Selma (USNM). Arkansas: Carlisle (MCZ); 
“Ark.” (Hayward, MCZ). Florida: Enterprise (USNM); 
Tampa (USNM) ; numerous specimens in Berlese samples from 
Alachua, Baker, Dade, Highlands, and Seminole counties (TCB). 
Georgia: “Georgia”, probably Habersham County (LeConte, 
MCZ); Galt’s Landing, Cherokee County (TCB). Indiana: 
5 miles west of Hardinsburg (USNM). Louisiana: Bay Sara 
(USNM); Houma (MCZ); Opelousas (Hayward, MCZ); Tal- 
lulah (USNM). Mississippi: Vicksburg (Casey, USNM). south 
CAROLINA: “S.C.” (MCZ). TENNESSEE: Bugger Swamp, near 
Cookeville, Putnam County (TCB) ; Bull Cave, Blount County 
(TCB). 
The range of M. aenescens is thus outlined as predominantly the 
Gulf Coastal Plain, with significant penetration northward into the 
Interior Low Plateaus (to Hardinsburg, Indiana). Leng (1920, 
p. 54) lists the species from “N.C.”, and it must certainly occur 
in Kentucky and possibly in southeastern Virginia. The apparent 
absence of Micratopus from southeastern Texas is probably a col- 
lecting accident. 
Discussion : — The species of Micratopus are differentiated with 
some difficulty, primarily because the range of variation within a 
species is difficult to determine with scattered material. Most of 
them, like M. aenescens , are probably rather widely distributed. The 
aedeagi resemble that of aenescens but are not easy to extract from 
dried specimens and are usually difficult or impossible to interpret 
unless several preparations are made. The accompanying figure of 
the aedeagus of M. aenescens (Fig. 2) was made with camera 
lucida but represents a composite of four aedeagi extracted from 
specimens at the same locality. I believe that the six minute sclerites 
of the internal sac, described in some detail for aenescens , have 
homologues in the Mexican and Central American species as well 
as those of the West Indies, and may prove to be of value in a 
diagnostic sense when the genus as a whole is investigated. 
The complex aedeagal structure presumably represents an aberrant 
and peculiar specialization. As such, it is of little help in determining 
the position of Micratopus within a bembidiine classificatory scheme. 
The external resemblances to Limnastis, however, leave little doubt 
that the two genera are closely related. Common features include 
