REVISION OF STEEPSIPTERA PIERCE. 33 



species were found to vary more readily on certain parts of the 

 face than on other parts. Thus A. decipiens Schenck has the clypeus 

 more frequently colored than the cheeks, and A. (schencki) lahiata 

 Schenck has the color more persistent on the cheeks than on the 

 clypeus. Chitty (1902) found a specimen of A. chrysosceles Kirby, 

 in which the clypeus lacked its usual conspicuous white color. In 

 all females of A. hi punctata Cresson seen by the author there have 

 been noticed the presence of yellow markings on the clypeus, which 

 should not normally occur. One female had five yellow spots irregu- 

 larly placed, while two others had a solid irregular blotch of yellow. 

 One female of A. cressoni which normally has the clypeus black in 

 that sex had yellow markings. 



h. The fovea (striga frontalis) , which in certain species is charac- 

 teristic of the female only, is found to some extent in the stylopized 

 male and suffers diminution in the stylopized female. Perez cites as 

 examples A. trimmerana Kirby and A. nigroaenea Kirby. 



c. The anal fimbria of the stylopized female sometimes entirely 

 disappears, or the length and number of hairs is considerably reduced. 

 On the other hand in the male the fifth and sixth segments of stylo- 

 pized individuals sometimes become clad with long hairs so that the 

 individual may be mistaken for a female. As exemplary of this 

 change Perez cites Andrena nigroeaenca Kirby. 



d. In the antennae the relative lengths of the second and third 

 joints of the funicle in the stylopized bee tend toward the characters 

 of the opposite sex. This change is very clearly shown in Andrena 

 trimmerana Kirby by Perez's figures (1886). 



e. Organs of work tend to assume the form found in the other sex. 

 The female tibia becomes slender, and less enlarged outwardly; the 

 hairs diminish in development and number; the tibial brush dis- 

 appears. The coxal and metathoracic scopa Qwuppes) suffer a 

 diminution in number, size, and curve of hairs. The female metatarsal 

 brushes become diminished by the lessening of the strength and num- 

 ber of hairs and the enlargement of the joint is diminished. The 

 males on the contrary sometimes show an enlargement of this joint 

 and a marked developement of the brush, as for instance A. trim- 

 merana Kirby (Perez, 1886). Mr. Crawford also noticed in several 

 stylopized Andrena in the writer's collection, a diminution in the 

 size of the tibise, but as no normal specimens were procurable at the 

 time more definite data can not be given at this writing. Note his 

 statement concerning Andrena crawfordi (p. 34). 



Primary sexual characters. — a. Ovipositor. — In stylopized females 

 the ovipositor becomes shortened. Perez records a female A. af- 

 zeliella convexiuscula with this organ shortened one-third. 



