772 Pomona Coij.ege Journai. of Entomology 



2. First segment of the tarsus eciual to one-hall' of the second. eulachnus 

 First segment of the tarsus not nearly eciual to half of the second. 3 



3. "Winged females usually present, tarsi of all legs two-segmented. 4 

 Winged females never found (as yet), tarsi of hind legs with but 



one segment, other two pairs of legs with two segments. trama 



■4. Wings carried pentwise (normally'), rostrum scarcely reaching be- 

 yond middle of the abdomen. 5 

 Wings carried horizontally (folded flat on the l)ack), rostrum of 



apterous forms much longer than the body. stomaphis 



5. Stigma not reaching to the wing tip, not exceptionally long. 6 

 Stigma exceptionally long, and reaching around the tip of the 



wing. longistigtna 



6. Abdomen with a horn-like tubercle on the median dorsum between 



the cornicles. hiberolaclinux 



Abdomen without the horn-like tubercle on the median dorsum. 7 



7. Ba.ses of the first and second discoidal veins usually close together, 



third discoidal often very faint, wings but slightly or rarely 

 clouded. lachnus 



Bases of first and second discoidals farther apart than in "Lach- 

 nus," third discoidal plain, wings often darkly clouded. ptcrochlorus 



8. Tarsi with first segment half as long as the second. essigella 

 Many of these genera are represented by but one species which forms the 



type, and but few- are found in California. It is, therefore, unnecessary to give 

 but the synonomy and type species of the most of them, while of those found in 

 this state I shall also give a key to the species. (The type species and generic 

 synonymy is strictly after Wilson.) 



EULACHNUS Del Guercio 

 Type Lachnus agilis Kalt. 



TRAMA I ley den 

 Type T. troglodytes Heyd. 



STOMAPHIS Walker 

 Type Aphis quercus Linn. 



LONGISTIGMA Wilson 

 Syn. Davisia Del Guercio 

 Type Aphis caryae Harris 



Tuberolachnus JNIordwilko 

 ? Syn. Schizolachnus Mord. • 

 Type Lachnus viminalis Fonsc. 

 T. vuiirnaiis (Fonsc.) Mord. On Salir fluviatilis Nutt. in Placer County 

 by Wm. Davidsen. P. C. Jr. But., Ill, p. 398, 1911. On .^. macrostachija Nutt. 

 and H. laevigata Bebb. in Ventura County by writer. (See in Litt.). 



