1895.] Entomology. 69 
sis’ published in these Transactions, Vol. XIX, pp. 296-300, Decem- 
ber, 1892. The superfamily term there suggested includes those fami- 
lies in which the hind tibiz are multispinose. These in our North 
American fauna are Ulopide, Ledridæ, Bythoscopide, Tettigoniidx 
and Jasside. The first of these might perhaps be removed from this 
series, and the second united with the Tettigoniide as a subfamily of 
equal value with Gyponinaand Tettigoniina. The position assigned to 
the family Bythoscopide is purely arbitrary, as it strictly parallels the 
Jasside, to which it is allied by Macropsis, and in a linear arrange- 
ment might with equal propriety follow the Tettigoniidz.” 
The Use of Parasitic and Predaceous Insects.—There has 
recently been much discussion concerning the utilization of parasites 
and predaceous insects in destroying injurious species. A knowledge 
of the conditions under which such insects act would render it evident 
that we cannot hope to exterminate any species of noxious insect by 
means of its parasites alone; and many too sanguine expectations 
have been aroused. But, on the whole, parasitic and predaceous 
insects are of immense service to man. Without them many plant 
feeding species would multiply to such an extent that the production 
of certain crops would require vastly more effort than it does now. 
To say, as has been said, that parasitic and predaceous insects have 
no economic value, is to put the case too strongly. Take, forexample, 
two crop pests of the first class—the army worm and the hessian fly. 
The history of a century shows that these insects fluctuate in numbers; 
that there are periods of immunity from their attacks followed by 
seasons when they are overwhelmingly abundant. It is universally 
acknowledged that in the case of the hessian fly, this periodicity is 
due almost entirely to the attacks of parasites, and in the case of the 
army worm to the attacks of parasites, predaceous enemies and infec- 
tious diseases. Remove these checks and what would be the result? 
The pests would keep up to the limits of their food supply and would 
necessitate the abandonment of the culture of the crops on which they 
feed. Take another case: Professor J. B. Smith has argued that 
“under ordinary conditions neither parasites nor predaceous insects 
advantage the farmer in the least,” and to prove it he cites this 
instance: “ Fifty per cent of the cutworms found in a field early in 
the season may prove to be infected with parasites, and none of the 
specimens so infested will ever change to moths that will reproduce 
their kind. Half of the entire brood has been practically destroyed 
and sometimes even a much larger proportion; but—and the ‘ but’ 
deserves to be spelled with capitals—these cutworms will not be 
