404 THE GYPSY ]MOTH. 



Spiders. 



At occasional intervals during the past four years, spiders 

 have been seen to attack and destroy the eggs, and also the 

 caterpillars and imagoes, of P. dispar. In the summer of 

 1895, a predaceous spider, found in Chelsea, was brought 

 into the insectary and supplied with gypsy moth cater- 

 pillars, which it readily destroyed. This spider was kindly 

 determined by Mr. J. H. Emerton as Phidippus trijmnctatus. 



Our common harvest spider (^Phalangium dorsatuni) was 

 found by Mr. Mosher feeding on a male gypsy moth. 



Mites have been found so frequently destroying the eggs 

 that we must acknowledge that in some localities they are 

 very important factors in reducing the numbers of the gypsy 

 moth. Mr. E. P. Felt observed the work of these mites on 

 the gypsy moth eggs in confinement, and found that they 

 destroyed the eggs very rapidly. They are most abundant 

 in the fall, but do not feed to any marked degree during 

 the winter. These mites were referred to Prof. Herbert 

 Osborn, who determined them as two diiierent species. The 

 first was JSFothrus, near ovivorus Pack. (Plate 53, Fig. 14), 

 and the other was Tromhidium hulbipes Pack. (Plate 53, 

 Fig. 15). A species of PJdoeothrips (Plate 63, Fig. 13) was 

 also found destroying the eggs. 



Insectivorous Vertebrates. 



Of the vertebrate enemies of the gypsy moth, the common 

 skunk, 3Iep>hitis mepliitica (Shaw), has been found feeding 

 upon the female moths which were laying their eggs at the 

 base of trees, or upon rocks, rubbish, etc. It is probable 

 that these animals also feed upon the pup» to some extent 

 in badly infested regions. 



The wood frog {Pana silvatica LeC.) has been reported 

 in one instance as attacking the female moths. In August, 

 1895, Mr. F. H. Mosher took a specimen of the tree frog 

 {Hyla picker ing a Holbr.), feeding upon the caterpillars 

 of the second brood of the gypsy moth, at Woburn. 



The common garden toad {Biifo Jentiginosus americanus 

 LeC.) was this year found by Mr. Kirkland to be devouring 



