50 HYMENOPTERA. 



1900, Saranac, N. Y. J. G. Needham " and bearing 6 apter- 

 ous males and 7 females. I am unable to distinguish these 

 specimens from the others labelled semblidis ; hence the 

 species occurs in the United States. 



In regard to the apterous males it may be recalled that 

 Riley once mentioned brachypterous specimens of mimdum 

 (Riley, 1885, Trichogramma pretiosa) but later Girault (1907 ^) 

 showed that these were simply imperfect specimens with the 

 wings as yet unfolded, or at least showed that the existence of 

 these so-called brachypterous specimens may have been thus 

 explained. This naturally leads to the question whether the 

 apterous males of semblidis or retorriduni may not be these 

 imperfect males, which having been killed too soon after their 

 emergence as adults to allow for the time necessary under 

 some conditions for the unfolding of the wings, appear to be 

 wingless ; but with these two species this can hardly be so 

 because (1) the antennas of all such males are different, a 

 correlation; and (2) the wings are very minute, barely indi- 

 cated, not large as is the case where development has been 

 mechanically arrested. 



Subsequent to its original description, this species has 

 attracted very little attention not being noticed systematic- 

 ally ; however, Silvestri (1908) has given us a very valuable 

 and thorough study of its development. 



In this connection I have forgotten to mention that the 

 apterous males are not very much smaller than the winged 

 specimens, not minute as with the apterous males of the 

 species retorridum. Of the specimens mentioned above, the 

 nineteen on the first slide listed have been deposited in the 

 collections of the Illinois State Laboratory of Natural His- 

 tory and given the accession number 44,188. 

 3. Pentarthron semifumatiiiii Perkins. 



This species very recently described by Perkins in the 

 current volume of Fauna Hawaiiensis^is the only well-marked 

 species of the genus but even at that is subject to some con- 

 fusion with the type species on account of the fact that the 



* I have merely seen the proof of this paper. It had not been pub- 

 lished up to December, 1910. 



