February, ’23] worthley: squash bug in Massachusetts 77 
Black-leaf “40,” 1-500. 
Not effective against nymphs older than 2d instar. 
Black-leaf “40,” 1-100, plus soap, 1 oz. per gallon. 
Not effective beyond 3d instar. 
Nicotine sulfate dust (homemade) about 2%. 
Not effective beyond 3d instar. 
Nicotine sulfate dust (Cal. Walnut Growers’ Ass’n. 1921). 
Not effective beyond 4th instar. 
Nicotine sulfate dust (Dosch 1922) 4%, killed 15% of adults. 
Nicotine sulfate dust (Dosch 1922) 2%, killed 15% of adults. 
Fish-oil soap (Sterlingworth) 1 lb. in 3 gals, water. 
About 80% effective against 3d instar nymphs. 
Fish-oil soap, 1 lb. in 3 gals, water plus 3 oz. sulfur. 
Partially effective against 4th instar nymphs, ineffective against adults. 
Fish-oil soap, 8 oz.; water, 1 gal.; sulfur, 2 oz.; ineffective against adults, and 
caused severe burning. 
The last-named mixture was reported by F. M. Wadley (4), p. 423, 
as a satisfactory means of killing adult squash bugs in Kansas. It was 
hailed with delight by the writer, and given repeated tests. 90% of 
adult bugs dipped in the mixture while it was warm were killed, but only 
a small percentage of those sprayed with the mixture while warm, and 
of those dipped or sprayed with the cold mixture, succumbed. In ad¬ 
dition, this material caused severe foliage burn. 
It will be noted that nicotine sulfate dust killed a few adults in the 
experiments. Three or four direct puffs were given the bugs, which 
resulted in a more liberal application than they would ordinarily get 
in field work. Still, the dust has killed adult bugs, and since there is 
reason to believe that the dusts will be improved, we may look forward 
with hope to the production of a material which can be used with safety 
and success even against an insect which has proved to be as resistant 
as the common squash bug. 
The Tachinid Parasite, Trichopoda pennipes Fabr. 
A more extensive paper on the biology of this species is being prepared 
by the writer, but a few statements may properly be given here. This 
beneficial fly has two generations yearly in Massachusetts. As many 
as 80% of overwintered squash bugs have been observed to bear eggs of 
the parasite. Many of these bugs, however, live to deposit a part, at 
least, of their eggs. 
The accompanying chart (fig. 3) explains the relation existing between 
parasite and host as it appeared in 1922 at Amherst. For economy in 
space, the egg stages, which are not significant in this connection, have 
been omitted. Flies of the second generation lay their eggs upon the 
