201 
Mr. Osborn agreed with Mr. Summers. 
The association then, on resolution, adjourned to meet at such time and 
place as may be decided upon by the executive officers. 
H. Garman, 
Secretary. 
DIPTEROUS PARASITES IN THEIR RELATION TO ECONOMIC ENTO- 
MOLOGY.* 
By C. H. Tyler Townsend, Kingston, Jamaica. 
It is a patent fact that no insect parasites of insects occur in the 
large series of orders known as the Ametabola, or those with an in- 
complete metamorphosis. They are to be found only in the series 
Metabola, or those orders which undergo a complete metamorphosis, 
and within this series they are confined to three orders. Certain pred- 
atory forms occur in the Neuroptera (as restricted) and the Lepidoptera, 
but the only orders containing true parasites of insects are the Cole- 
optera, Hymenoptera, and Diptera. It is, therefore, evident that para- 
sitism on insects is a perquisite of the higher and more developed orders, 
and usually, within these orders, of the higher and more specialized 
groups. Moreover, the higher the order, the greater is the percentage 
of parasitism which it contains. The Coleoptera contains an extremely 
small percentage, belonging to about four small families. The Hymen- 
optera contains a large percentage, distributed, however, through but 
a half dozen or so of families, and comprising mostly very small para- 
sites. The Diptera contains probably the greatest percentage, distrib- 
uted through about seventeen families. 
Still another point remains to be noticed, and that is the diversity of 
the parasitism, or the number of orders upon which each of the three 
named is parasitic. Of the sixteen orders of insects, as evolved by 
Brauer and now generally^accepted, only five are subject to parasitism. 
These are the Orthoptera, Hemiptera, Coleoptera, Lepidoptera, and 
Hymenoptera. The parasitic Coleoptera are confined in their attacks 
to the first and last of these. The Hymenoptera attack the last four, 
including their own order. The Diptera, however, furnish parasites 
upon all five of these orders. 
Last of all, two significant facts strike us: First, that the Diptera 
themselves are not attacked by any parasites, not even by members of 
their own order, if we may except a species of Phora which is said to 
destroy the larvae of the Silk -worm Tachinid in India. There is no rea- 
son, however, for believing that this is a true parasite. While the 
Coleoptera are subject to parasitism from the Hymenoptera and Dip- 
tera, the Hymenoptera are subject to attack from all three (including 
* This paper reached me too late for presentation at the Madison meeting. — H. G. 
