GENERIC CLASSIFICATION OF APHIDIDAE. 61 



Genus PENTALONIA Coquerel. 

 Plate VIII, II-MM. 

 1859. Pentalonia Coquerel, Ann. Ent. Soe. France, Ser. 3, v. 7, p. 259. 



The genus Pentalonia Coquerel is a very peculiar one and possesses 

 a venation unlike that of any other in the Aphididae. It is, however, 

 only a little further development of the condition met with in 

 Idiopterus, which is the less specialized of the two genera. 



Characters. — Head with prominent antenna! tubercles which, are, more especially 

 in the apterous form, projected inward, gibbous and somewhat Myzus-like in appear- 

 ance. Antennse of six segments, armed with subcircular sensoria, the first segment 

 gibbous like the antennal tubercles. Cornicles somewhat constricted near then* 

 middle, then again somewhat swollen near their distal extremity. Cauda rather small 

 but elongate, subcorneal, slightly constricted about the middle. Fore wings with the 

 radial sector extending abruptly downward and meeting the upper branch of the media 

 with which it fuses but is diverted again toward its natural course near the tip of the 

 wing. A closed cell is thus formed by the radial sector and the media but at the 

 margin of the wing there are the same veins as in the Aphidini (Plate VIII, JJ.) 

 Hind wings very much reduced, cubitus absent. 



Type (monotypical) , Pentalonia nigronervosa Cql. 



Subfamily II, MINDARINAE. 



It has been the custom to consider the genus Mindarus as closely re- 

 lated to the Pemphigini, but the writer is unable to do this and concludes 

 that it must represent a subfamily in itself. In some ways abietinus 

 is the most primitive living aphid. It is, in fact, the only one which 

 has retained the general wing structure which is predominant in the 

 fossil forms. It is true that the venation is more reduced than in 

 some of the other subfamilies, but the type of wing in regard to the 

 stigma formation is exactly like most fossil wings and unlike the 

 wings of other living forms. Many of the characters suggest the 

 Eriosomatinae and the genus is no doubt very similar to the ancestors 

 of the insects in that subfamily. The antennal structure and general 

 form are like those in the Eriosomatinae. The sexes, too, are apterous, 

 but though they have developed the small apterous condition they are 

 in many ways more primitive than are the sexes of the Eriosomatinae. 

 The male is small and suggests the condition in those forms. The 

 peculiar habit of copulation is similar, in that the male mounts the 

 female and may remain there inactive for a very long period. The 

 writer has observed a male of Eriosoma lanigerum clinging thus to a 

 female for 48 hours. The sexes of Mindarus, however, have not 

 lost the beak and the male feeds on the juices of its host. In this 

 regard they are more primitive than sexes in the Eriosomatinae. 

 The oviparous female, moreover, develops her ovaries and produces 

 as high as 8 or 9 eggs, in striking contrast with the ovipara in the 

 Eriosomatinae. It is a much less specialized condition. In regard 

 to the alate form the shape of the cauda is quite different from that 

 met with in the Eriosomatinae. 



