FOUR RARE APHID GENERA FROM MAINE. 247 



which may be absent but is apparently characteristic as it is 

 usually found both in the mature apterous form and in the 

 young nymphs. Cornicles long (0.45 mm.) cylindrical and dark 

 brown. Total length of body 1.65 mm. Color description from 

 living material. Measurements from balsam mounts. Maine 

 collection number 98-06. Figures 213, 214. 



Bibliography. 



1886. Mastopoda pteridis, Oestlund. List Minn. Aphid, p. 53. Original 



description. 



1887. Mastopoda pteridis, Oestlund. Aphid, of Minn. p. 49. Descrip- 



tion and brief account. 

 1898. Mastopoda pteridis, Packard. Textbook of Ent. pp. 103, 104. 



Fig. 114. Figures the leg. 

 1910. Wilson. Pro. Ent. Soc. Wash. Vol. 12, p. 28. Mastopoda 



pteridis, Oestlund, is by error considered a synonym of Aphis 



pteris-aquilinoides, Raf.* 



Explanation of Plates. 



Figures 203-207 were drawn by Miss Charlotte M. King. 

 The photomicrographs were taken by Mr. Royden L. Hammond. 



Figs. 198-205. Sipha glyceriae. 198, Winged viviparous 

 form; 199, pupa; 200, wings; 201, apterous viviparous form; 

 202, tip of abdomen of apterous viviparous form giving a good 

 view of the cauda ; 203, antenna of winged viviparous form ; 

 204, antenna of apterous viviparous form; 205, antenna of pupa. 



Figs. 206-212. Mindariis ahietinus. 206, Antenna of winged 

 viviparous form ; 207, antenna of pupa ; 208, wings ; 209, tip 

 of abdomen of winged form lateral aspect; 210, tip of abdomen 



*Although it would seem to be impossible on the basis of the original 

 description of Aphis pteris-aquilinoides to recognize this species if one 

 should chance to re-discover it, fortunately Rafinesque included one char- 

 acter by which his species can readily be separated from pteridis 

 Oestlund for he states that the "appendages" (/. c. cornicles) are short 

 in pteris-aquilinoides . It is perhaps safe to hazard the guess that even 

 Rafinesque would have noticed the atrophy of the tarsi if he had col- 

 lected so remarkable a species. 



As Rafinesque's papers are not easily accessible, his description of 

 Aphis pteris-aquilinoides is quoted entire as follows : 



"6. Aphis Pteris-aquilinoides. (P. aquilina Amer. Aiict.) Body pale 

 green, oboval, one line long; eyes brown, antens half a line long; ap- 

 pendages very short." Rafinesque designated the cornicles by the term 

 "appendages." 



