54 SEVENTEENTH Report STATE ENTOMOLOGIST OF MINNESOTA—1918 
I. Trine LACHNINI 
Kaltenbach, 1843. Monogr. Sub **) Radialzelle ete. 
Koch, 1855. Die Pflanzenl. Heft 7. Sub Lachnus (genus s. str.) 
Mordwilko, 1895 Zool. Anzeig. Vol 18. Sub “Baumliéiuse”. 
Cholodkovsky, 1898. Beitr. Monogr. Sub ‘“‘Coniferen—lduse.” 
Hartig (1841), in his definition of the genus based on venation, 
undoubtedly had in mind a true Lachnus as the type but included also 
the heterogeneous forms of Burmeister to which he adds further. 
Kaltenbach (1843) recognized this polygeneric condition and remarks 
that the genus can not long continue as such; he separates the in- 
cluded forms in two sections, the second of which in main corresponds 
to the present tribe. Koch (1855) restricts the genus Lachnus to in- 
clude the conifer forms. Mordwilko (1895) treats the genus Lachnus 
(Burm.) Koch in a tribal sense, in which he is followed by Cholod- 
kovsky (1898). 
Morphological characters. The distinguishing characters of the 
present tribe are found in the venation of the wings. The stigma is 
long and narrow, and the stigmal vein takes its origin near the distal 
end of the more or less truncated stigma and runs as a short and 
straight vein to the margin of the wing. The media appears as a faint 
and indistinct vein; it is normally two-branched but sometimes with 
only one branch or simple. The Lachnini are further distinguished 
by their five-jointed rostrum. 
Biological characters. The Lachnini are mostly large; in color 
brown or black, those feeding on the needles alone show the green 
so common and characteristic of the family. They are all but confined 
to conifers, feeding on the trunk and limbs, or on the tender twigs 
and needles. They have a wide distribution in the temperate zone, but 
have the appearance of a vanishing group with the gradual restriction 
ra) 
and disappearance of the Conifera. 
2. TRinE PTEROCHLORINI 
tondani, 1848. Ann. Sci. Nat. Bologna, Vol. 9. Sub Pterochlorus (genus). 
Koch, 1855. Die Pflanzenl. Heft 7. Sub Dryobius (genus). 
The Pterochlorini are here recognized for the first time as a dis- 
tinct tribe; the forms included have hitherto been considered with the 
Lachnini. Rondani (1848) first established the genus Pterochlorus 
with Aphis roboris L. as type. Koch (1855), not aware of Rondani’s 
paper, proposed the generic term Dryobius for the same species as 
type, to which he added a second also from the oak. The tribe is 
