160 TRANSACTIONS OF THE ILLINOIS 



attached to the under side of the larvse of the almond and peach trees. 

 It also produces the same effect upon the leaves as the A. persicce, at least 

 so far as the crisping and wrinkling are concerned. 



The body measures only about three-hundredths of an inch in 

 length ; to the tip of the wings, about one-twelfth of an inch, or less. 

 The body is entirely green; antennae, brownish; the legs are green, 

 except tlie tips of the thighs and tibiae, which are yellowish ; wings pel- 

 lucid, very long ; veins, pale yellow or greenish. 



I have not met with this specimen, nor have I seen any notice of its 

 appearance in this country. It is therefore possible it has not been 

 imported, although the great probability is that it has. I give a brief 

 description, so that it may be known if found occurring on the peach 

 trees of our State. 



21. Aphis {Rhopalosiphuni) ribris, Linn. The Currant Plant-louse. 



This species has been transferred by Koch to his genus Rhopalosi- 

 phuni. Whether the species found on our currant bushes is the same as 

 that found in Europe I think somewhat doubtful, notwithstanding the 

 apparent common assent to this conclusion, but will not attempt a dis- 

 cussion of the point at this time. It is usually found on the currant 

 bushes in May and June, and later fixed upon the young shoots and on 

 the under side of the leaf. They cause the latter to crisp, fade and 

 incline at the points attacked; to assume a reddish tinge, producing con- 

 cavities on the under side, with corresponding convexities on the upper 

 side. Each of these concavities is produced by a little colony, the 

 members of which, working close together, depriving this part of the 

 iinder dermal covering of its sap, causes it to contract and assume the 

 form of a miniature basin. 



The winged individuals measure about, or a little over, one-tenth of 

 an inch in length to the tip of the wings; the body is greenish ; antennae, 

 yellowish or greenish ; legs of the same color, except the end of the tibiae 

 and the tarsi or feet, which are dusky ; wings, pellucid. 



The apterous individuals measure about one-tw^elfth of an inch in 

 length ; dark velvety green ; antennae not quite as long as the body, 

 setaceous, pale green at the base, dusky at the tips ; eyes, black ; honey 

 tubes short, pale green. The color varies from dark green to yellowish. 



Although common, throughout this country, on the red currant, it 

 has not been observed either upon the gooseberry or black currant. It 

 is often so abundant in the southern portion of the State as to leave 

 scarcely a leaf unblistered. 



The foregoing list includes the principal species of this genus so far 

 determined, which are found on cultivated fruit plants. Most, if not all, 

 of them have been observed in Illinois, and therefore deserve the attention 

 of our horticulturists. 



2 2. Aphis [Sipho7iophora) rosce. The Rose Plant-louse. 



I find no notice of this species in any of the entomological works of 

 this country, except a mere mention of the name, yet that we have a Rose 



