Girault, Trichogrammatidw. 
81 
THE CHALCIDOID FAMILY T RICHO GRA MM A TIDJE. 
I. tables of the subfamilies and genera and revised 
CATALOGUE. 
By A. A. Girault 
i. introductory. 
The family Trichogrammatidw was first recognized as such by 
Arnold Foerster in 1856. Since that time it has held its identity. 
A half century later, Ashmead (1904a) recognized two subfam¬ 
ilies, founded upon the two groups of genera first outlined by 
Haliday in 1851. The family seems to be worthy of the rank 
attributed to it, although it is certainly a derivative of insects like 
Xhz Aphelininw of the Bulophidw or some Aphelinine-like Eulo- 
phid. Certain of the genera bear a number of encyrtine characters 
but the assemblage of characters more nearly resembles those of 
the Bulophidce. Indeed, are not the members of this family 
merely Eudophids which have lost one tarsal joint and which have 
other characters and habits giving them group distinctness ? 
The family seems to be of comparatively recent origin, more 
youthful than the Eulophids; no fossil species have been discov¬ 
ered ; the species of such genera as are well known appear to be 
highly variable and still in process of formation, a criterion which 
I believe denotes comparative youthfulness; otherwise we should 
expect to find gaps between them. Moreover, minuteness is a 
characteristic of the group. The genera are also in many cases 
indistinct, bearing this out more conclusively. In a word, we 
appear to have here a natural group evolved from an Aphelinine- 
like ancestor and which is still evolving, not having as yet reached 
comparative stability*. Whether we call this group a family or 
subfamily matters not. 
For the sake of clearness and convenience the family Tricho¬ 
grammatidw was divided by Ashmead (1904a) into two group- 
* On the other hand, the group has been in existence long enough to 
develop parthenogenesis and both color and sexual dimorphism. 
There are no other Chalcidids known to have two structurally dis¬ 
tinct male forms and this phenomenon is rare, if not absent, in all 
other Hymenopterousi groups, excepting ants. It is therefore a spe¬ 
cial development. Parthenogenesis may be a persistence here. It 
is true, too, that great variability indicates old age but with this 
group it is not excessive. 
