Packard.] 101 [Feb. 3, 



RECAPITULATION OF THE MOUE SALIENT ONTOGENETIC FEATURES. 



A. Congenital Adaptational Features. 



1. Tlie larva is hatched without any tubercles. 



3. The glandular hairs are of the same size and shape in the dorsal and 

 subdorsal rows; being short, with a tine at the middle, and forked at the 

 truncated end. 



8. The body is more cylindrical than in the last stages and not skifi-like, 

 and the segments are distinct and simple. 



4. The body is at first colorless. 



B. Evolution of Adaptational Features. 



1. The body becomes skiff-like when 5.5 mm. in length. 



2. The color is pea-green, like that of the leaf it feeds on, with straw- 

 yellowish marks and spots. 



3. The skin becomes rough and granulated, and the plateau distinctly 

 marked in Stage III or IV. 



4. In the last stage the minute spines disappear. 



Young Larva of Heterogenea sp. 



Very near B.'s drawing, August 8, 1888, on the wild cherry. It must 

 be that species, as both want the anterior median reddish dorsal stripe. 



My specimen, found on under side of leaf of wild cherry, September, 

 1890, only differs from Bridgham's figure in wanting the row of small 

 tubercles on each side ; these may be developed in the penultimate stage, 

 but my specimen is of the same length (5.5 mm. b}- 3.5 mm. wide). It 

 is closely allied to if not the same as the Heterogenea testacea found on the 

 beech. It differs from those, and an unpublished figure by Emerton, 

 however, in the line from the front edge of the second thoracic segment 

 to the cross being obsolete, and simply represented by a faint, small, 

 transverse discoloration, where two are represented in Bridgham's Fig. A. 

 The red Greek cross is not very well marked, as the arms of the cross are 

 very broad and triangular, and the base does not reach the end of the 

 body. But the colors are as in H. flexuosa, the general color purple 

 madder, with a longitudinally oblong pale Venetian-reddish patch con- 

 taining still paler spots, the whole margined with deep brickred, and 

 edged on the outside with yellow. 



This and other Heterogeneas look just like a reddish patch often to be 

 seen on the under side of some of the cherry leaves and afford remark- 

 able examples of protective coloration. 



Full-grown Larva op Heterogenea sp. 



Occurred on the under side of leaf of oak at Brunswick, Me., Septem- 

 ber 6 (Bridgham's MS. Fig. 273). 



