THE CANADIAN ENTOMOLOGIST. 35 



This study showed that the measurements given in the description 

 of the species by Prof. Johnson represented specimens in May and June, 

 when the species is at its maximum size, but specimens much smaller 

 were found at that season, and those collected in October of 1S99 and 

 1900 were uniformly smaller. It was found that the average size of 

 specimens measured was as near that of JY. pisi, Kalt., of Oestlund, as 

 iV. destructor, Johns., with no marked difference in colour. A careful 

 review of European literature showed the size of AT. pisi, Kalt., as given 

 by different writers, to be quite variable; the length, for instance, as given 

 by Koch (No. 7) is 3.3 mm., while Buckton (No. 9) gives 2.27 mm., and 

 Taschenberg states that the winged female is slightly shorter than the 

 wingless (No. 25), which he describes as 4 mm. long. The coloration as 

 given by these writers is also variable. 



In October, 1900, a form of the winged female (No. 11) — described 

 below — was found migrating from peas to clover, which was much 

 darker and smaller than the summer broods and in many respects more 

 similar to some of the descriptions of N. pisi, and at the same time the 

 apterous females and nymphs were distinctly pulverulent, which was not 

 observed in June, but is mentioned in descriptions of pisi. A few 

 winged males (No. 17) — described below — were also secured. 



Having become well convinced of the identity of the two species, 

 specimens of N. pisi, Kalt., were secured from Mr. G. B. Buckton, F.R.S., 

 Haslemere, Eng., who kindly lent me two slides containing several 

 specimens in Canada balsam. The specimens of one slide, collected at 

 "Southgate, June 17, -47" (1847 ? ) (Nos. 1 and 18), were of exactly the 

 same size as N. destructor as described by Prof. Johnson, with exception 

 of segment VI. of the antennae being very much shorter. They also 

 differed in having the cornicles and antennae (PI. I., ia., icl.) considerably 

 thicker than the smaller specimens of destructor, though very probably 

 this is largely due to their having been flattened by the pressure of the 

 cover glass and the drying of the balsam. The surface of the tips of the 

 cornicles is reticulated, which has not been observed in typical destructor. 

 None of these differences can, however, be considered as of sufficient 

 value to separate the species, especially when one considers the variability 

 of the species as given by European writers. The specimens of the 

 other slide, marked by Mr. Buckton, " Siphonophora pisi? — Fool's 

 Parsley," are considerably smaller, but are similar to the smaller forms of 

 destrtictor found here, and lack the reticulation on the cornicles. There 



