THE CANADIAN ENTOMOLOGIST. 231 



The Succeeding Stages. — As Edwards has pointed out, the coloration 

 has altered considerably by the time the first moult is passed. The general 

 colour is light green, with markings distributed as in irus and augustus 

 (when mature), these markings of a yellow-green, not the intense yellow- 

 green oi augustus, but of a tint that may properly be described as "flat,'' 

 and lacking in brilliancy. On either side of the faint (and not always 

 present) mediodorsal yellow-green stripe the dorsal blood-vessel shows 

 dull red-brown. Moreover, all the body-green [i.e., all excepting the 

 mediodorsal stripe, the summits of the laterodorsal ridge, the oblique 

 lateral dashes — in' Henrici run in with the laterodorsal marks and not 

 distinguishable from them — the spots which represent the vestige of a 

 spiracular line, and the stripe on the substigmatal fold, all of which are 

 markings due to modification of the tissues) — with the exception then of 

 these markings thewJiole upper part of the larva may be a deep red-brown. 

 There are all degrees of intergrading between the two extremes, but the 

 dorsal stripe was red-brozvn in all of the larvce carried through to the 

 second stage. As no such colour appeared in any of the hundred-odd 

 irus or in any of the six augustus examined, it is probably a reliable 

 diagnostic character for this stage, and as it persists throughout larval 

 life, for the subsequent stages also.* 



The more elongate shape and the protninefit ridge on each of the first 

 eight abdominal segments differentiate the larva of Henrici from the con- 

 generic caterpillars without reference to coloration, though the differences in 

 the latter respect are more striking, irus being pale pea-pod-green, with faint 

 white or very light green markings, augustus z'/z'/V/ yellow-green, with (or 

 without) bright yellow markings, and Henrici dark green or ^'port-wine- 

 red^'' with broad, prominent markings of a dull, flat yellow-green. These 

 points will be discussed and illustrated later. 



Larval Variation. — In the spring of 1881 Mr. Edwards found his 

 first caterpillar of this species feeding on a wild plum. It was nearly full- 

 grown, and eventually became a chrysalis which did not disclose the 

 imago. It was described as having been ''entirely green in shades, except 

 for two subdorsal red-brown stripes." The following year eggs were 

 secured from an imprisoned butterfly, and one larva was bred to maturity 

 on plum ; when full-grown it differed from the other caterpillar in that the 



*The dorsum is red in /. polios duriiijj- the second larval instar, but other 

 characters make the separation of Henrici and polios a simple matter. 



