34 Rev, T. A. Marshall's Monograph of 



contained in the first table, but whose peculiarities are so 

 marked that they can be recognised apart from their 

 females ; the number of these is very restricted, doubtful 

 forms, which are many, having been excluded. 



Table of Species. 

 1. Males and Females. 



(2) 1. Apterous in the female sex, male un- 



known 1. ephippium, Hal. 



(1) 2. Winged in both sexes 3 



(4) 3. First cubital areolet limited on the 



lower side by the cubital nervure, 



sometimes not very distinctly 5 



(3) 4. First cubital areolet entirely effaced ... 65 



(6) 5. Abdomen linear, very slender, three 



times as long as the head and thorax.. 2. Zow(/«/««, Marsh. 



(5) 6. Abdomen lanceolate, not remarkably 



slender, more or less dilated in the 

 middle, only a little longer than the 

 head and thorax 7 



(8) 7. Antennae of the 9 composed of 20-22 



joints, those of the S 25-jointed. Large 

 species {Pinicolte, Hal.) attacking 

 the large pucerons of coniferous trees 

 {Lackmis, &c.) 9 



(7) 8. Antennse S 9 with fewer joints. Smaller 



species, attacking the typical Aphiclw 17 



(10) 9. Abdomen yellow, at least posteriorly ... 11 



(9) 10. Abdomen black or fuscous, with the 



two first sutures pale ; or cinctured 



with yellow bands, black posteriorly 13 



(12) 11. Antennfe black at the apex ; wings en- 



tirely hyaline ; 1st segment gradually 



dilated from base to apex ; terebra . 



curved, ascending ; tubercles of 1st 



segment situated before the middle... 3. pictus, Hal. 



(11) 12. Antennae testaceous at the apex; wings 



infumated beneath the stigma and 

 towards the tip; 1st segment linear 

 as far as the tubercles, which are 

 placed in the middle, the condylus 

 dilated ; terebra straight, horizontal... 4. infulaivf, Hal. 



(14) 13. Abdomen with only the two first sutures 



more or less pale 15 



(13) 14. Abdomen cinctured with distinct yel- 



low bands, of which the anterior is 



broadest 5. ahietis, Marsh. 



(16) 15. First segment linear as far as the 



tubercles, condylus gradually dilated; 



terebra obtuse, horizoutal 6. /)('///, Hal. 



(15) 16. First segment linear, condylus not di- 



lated ; terebra acute, ascending 7. laricis, Hii\. 



(18) 17. Antennae of the 9 17-20-jointed (in 



^. «rOT 21-jointed) 19 



(17) 18. Antennse of the 9 12-16-jointed 37 



(20) 19. Antennae ferruginous 8. tirticiti, Ha.]. 



(19) 20. Antennaj black or blackish 21 



(22) 21. Abdomen, from the base of the 2nd seg- 

 ment, entirely testaceous 9. (jreffariits. Marsh. 



