Robert B. Benson.
Blasticotomidæ in the Miocene of Florissant, Colorado (Hymenoptera Symphyta).
Psyche 49:47-48, 1942.

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19421 Miocene Blasticotomids 4 7
BLASTICOTOMID% IN THE MIOCENE OF FLORIS- SANT, COLORADO (HYMENOPTERA SYMPHYTA)
British Museum, London
Among the fossil sawflies discovered at Florissant, Colorado, in Miocene beds was one described by Brues (1908) as being a very peculiar Tenthredinid, which he placed in a new genus and called Paremphytus ostentatus. At the same time he con- fessed that he had "not been able to locate the specimen with any degree of satisfaction." Rohwer (1908, p. 526) is also struck by the remarkable wing-venation of this insect, which he placed in the Tenthredinid subfamily Phyllotominse. Neither of these authors was familiar with the Blastico- tomidse which are only known now to occur in the palsearctic region and neither of them therefore recognized the remarkably similar wing-venation of the fossil Paremphytus and the living Blasticotoma (cf. Brues 1908, fig. 6 and MacGillivray 1906, fig. 44).
The placing of Paremphytus in the Blasticotomidse is further supported by its apparently argid-like antennae as in that family.
Brues says: "Antennae stout and thick and possibly with the last joint long as in Arge and its allies. However, this charac- ter is not very plainly to be seen on the specimen. . . . The similarity of the antennae to those of Arge et al. is very striking, but it is possible that the last joint is in reality several closely united ones."
Unfortunately without the claws of the insect it is impossible to tell whether Paremphytus is likely to be synonymous with either of the two known recent genera of Blasticotomidse, Blasticotoma or Runaria. Living members of the family now represent five known species and one subspecies. B. filiceti
Klug is known in Europe and also as a distinct subspecies in east Asia including Japan. The four other species are limited to Japan and east Asia. As these insects are not often found on the wing even in districts where the larvse are known to Pu&e 49:47-48 ( 1942). hup ttpsychu einclub org/49/49-IM7.htiiil



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48 Psyche [Sept .-Dec.
occur, living representatives of the family may yet be found in North America. The only described larva, that of B. filiceti Klug (Meijere 191 1, p. 86, pl. v, figs. 1-12), is without abdomi- nal legs and bores in a fern-stem, producing a peculiar irregular ball of
froth about the size of a walnut on the side of the stem. The presence of the insect in a district is usually most easily detected by these balls of froth. The representation of this family among the Florissant fos- sils is specially interesting because of the extreme rarity of the adults of the living species and suggests that they may have been more common as well as more widely distributed in Mio- cene times.
Brues, C. T.
1908. New Phytophagous Hymenoptera from the Tertiary of Florissant, Colorado. Bull. Mus. Comp. 2001. Harvard, 51:257-276, figs. 1-10.
MacGillivray, A. D.
1906. A study of the wings of the Tenthredinoidea, a superfamily of Hymenoptera. Proc. U. S. Nat. Mus., 29:569-654, figs. 1-97. Meijere, J. C. H. de. 1911. Ueber in Farnen parasitierende Hymenopteren- und Dipteren-Larven. Tijdschr. Ent., Amsterdam, 54:80-187, pis. 5-7 (figs. 1-40).
Rohwer, S. A. 1908. On the Tenthredinoidea of the Florissant shales. Bull. American Mus. Nut. Hist., 24:521-530, figs. 1 a-e.



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