PSYCHE 
VOL. XXXIV. OCTOBER 1927 No. 5 
THE MALE GENITAL TUBE OF SOME OF THE SPECIES 
OF THE GENUS SCYMNUS (COLEOPTERA, FAM. 
COCCINELLIDJE) 1 
By J. W. Wilson. 
The genus Scymnus is one of the largest in the family Coc- 
cinellidse and one in which the species are very hard to determine 
on account of their remarkable uniformity in appearance. The 
adult beetles are small, ranging from 1.1 mm. to approximately 
3 mm. in length, rounded to oblong-oval in shape, pubescent, 
with six ventral abdominal segments showing, and the legs free. 
The color markings are quite constant, “Color characters have 
their utility in the separation of species of Scymnus, but some 
care and no little experience is required in their use” (Horn 
1895). Casey (1899) in his revision of the Coccinellidse used 
color to a great extent in the separation of the species. The 
prosternal carinse and the abdominal plates or metacoxal lines 
are other characters which are very useful in this group. The 
secondary sexual characters of the male are quite distinct in 
most of the species, but have been mentioned in the description 
of very few of the species. 
Leng (1920) lists one hundred and nineteen species from 
North America, sixty-five of which were described by Casey, 
seventeen by Leconte, fourteen by Horn, ten by Mulsant, four 
by Fall, three by Crotch, three by Melsheimer, one by Blatch- 
ley, and one by Say. Casey believed that the number of species 
would be increased in the future instead of decreased. Nothing 
has been done with the genus Scymnus since Casey’s “Revision 
of the American Coccinellidse,” except the description of four 
species by Fall and one by Blatchley. 
Contributions from the Entomological Laboratory of the Bussey Insti- 
tution, Harvard University, No. 276 
