166 .Bulletin Wisconsin Natural History Society [Vol. 11, No. 4 
knowledge of the group, much of which unfortunately but served 
to lead to confusion. This was due to the great difficulty attending 
the study of this group and mainly to wrong antennal perceptions. 
Very few new groups were added during these years but the num- 
ber of known species was sensibly increased and the knowledge 
of the complex host relations of some of the commoner species 
much enhanced. American entomologists took the lead. In 1871, 
Charles Valentine Riley described Trichogramma minutum which 
subsequently has led to confusion by Riley’s proposal of Pent- 
arthron *as a generic name for it. Consultation of Riley’s descrip- 
tion and figures of this insect (Riley, 1871, 1879, 1881) and its 
synonym described later — pretiosum — shows distinctly that Riley 
did not count the ring-joint of the antenna as a true joint as he 
states (Riley, 1879), and both of his figures of the two species are 
identical in essential details, especially as regards antennal struc- 
tures. For the time at which they were drawn and printed these 
figures are excellent likenesses of the same thing drawn at different 
times and from different material under different conditions. 
Since then nearly all systematic workers in this group, excepting 
Ashmead and one or two c thers of less importance, have strongly 
suspected Pentarthron to be the same as Trichogramma Westwood; 
from all of the evidence obtainable from the literature, and from 
the general probabilities, I shall consider the inferences drawn by 
these experienced men to be correct and shall not hesitate at all 
in agreeing with Aurivillius (1898) in placing Pentarthron Riley 
( = Pentarthrum Riley, de Dalla Torre, 1898) among the synonyms 
of Trichogramma Westwood. 3 
In connection with the Trichogrammatidae, other than histori- 
cally, the only reason for calling attention to the Schetsen of 
Snellen van Vollenhoven (1871) is for the purpose of warning others 
against putting any trust at all in the figures given of the genera 
Trichogramma Westwood, Poropoea Foerster, Chaetostricha Haliday 
and Centrobia Foerster, a condition of affairs most unfortunate 
considering the labor involved, the good general execution of the 
figures, and the great aid, which if accurate, these figures would 
have been. The figures are good as meaningless drawings, but as 
3 See Girault 1911j , where the matter is fully treated. Dr. L. O. Howard had informed me that 
he has seen the type of Trichogramma and that it is the same as the common minutum Riley — 
that is, generically. 
