328 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 4 



the head of the wingless being yellow.^ Nothing has since been added 

 to our knowledge of the species, though it has been mentioned in 

 literature by several authors, excepting the notes made by MonelP 

 from an examination of a single winged specimen in Riley's cabinet, 



d 



Fig. 10. Sketch of wing of M. fragarice var. immacullata Riley [After Monell]. 



and by Mr. Theo. Pergande^ who, after examining the few poorly 



preserved specimens (probably pinned) of Riley's immaculata, states 



that his Macrosiphum trifolii is distinct. Nor has it been identified 



since the original description, and it is probable that the species 



referred to by Riley as immaculata is some other — possibly A. forbesi. 



Mr. Monell has very kindly placed at my disposal the original notes 



which he made August 21, 1876, from a specimen in Riley's collection. 



They are as follows: 



"62° Cell formed by secondary branches of cubital very small (a). The upper 

 branch in S. fragaricc Koch (see pi. XXXII Pflanzenlause) being quite equal in length 

 to part marked b in explanatory sketch. The first and second discoidal are almost 

 parallel in Koch's figure [while in immaculata] space at apices [c d] is little over twice 

 as wide as space at bases [e f]. Hind wings have apex more pointed than in Koch's 

 figures. It has two discoidals, costal vein seems rather straight. Little (hooks) 

 protuberances upon costal edge (Koch's figure does not show costal edge). Drawn 

 from dried specimen in Mr. Riley's cabinet under small lens August 21, 1876." 



The drawing referred to by Mr. Monell is only 13 mm. in length, 

 and I have drawn free-hand (fig. 10) a reproduction which, for the 

 purpose here intended, is sufficiently accurate. The venation agrees 

 quite well with Aphis forbesi Weed, * but differs from that species in 

 lacking the black lateral abdominal spots. Although these notes are 

 insufficient to draw any reliable conclusion, they are given with the 

 hope that they may later be a help in a solution of the problem. 

 This species has never been positively reported from Illinois. 



m. gerardice Thos.: 8th Rep. State Ent. 111. (1880), p. 66. This 

 species has not been reported since the original description. 



iMr. J. T. Monell, in a letter dated December 7, 1910, writes: "There is no 

 formal description, but simply what Thomas gives in his Illinois report. I may 

 note that Riley did not at that date know a Siphonophora from an Aphis." 



2Bull. U. S.' Geol. and Geog. Surv., Vol. V (1879), p. 22. 



sBull. U. S. Depart. Agr., Div. Ent., No. 44 (1909), p. 22. 



4 The venation of forbesi, however, varies considerably. 



