r,70 ASILID^ 



thickened, and the front pair with more or less long and dense pubescence ; legs 

 sometimes entirely black, or sometimes reddish on just the base of or on the whole 

 of the tibiae or even on part of the femora. Bristles strong on the posterior femora 

 and on all the tibiae and tarsi, and in some species also beneath the front femora 

 (though sometimes in the female only), but in our two British species without any 

 bristles beneath the front femora in either sex. 



Wings normal. Alar squamae with long conspicuous dense fringes. 



This genus is most closely allied to Eutolmus, and in some cases the 

 males cannot be generically distinguished ; in fact it requires the know- 

 ledge of both sexes to locate a species with certainty in this genus. Any 

 species in which the male has a produced hindmargin of the eighth ventral 

 segment and the female has free anal lamellse is a Macliimus ; but if the 

 male only be known it must be searched for in Mnchimus or in those 

 species of Uutolmas in which the eighth ventral segment is produced ; 

 while if the female only be known it may be distinguished at once from 

 Eutolmus and Dysmachus by the free anal lamellse, from Neoitamus and 

 Paritamus by the less sharply defined orange colour on the tibiae, the 

 normally formed and less elongate ovipositor, the greyer colour, the 

 presence of bristles on the thoracic stripes, and the shorter simpler 

 postocular festoon, and (as far as British genera are concerned) from 

 Epitriptus by its larger size and darker coloring; these and other dis- 

 tinctions are mentioned under the descriptions of the allied genera. 



Macliimus contains about twenty-five Palciearctic species of which only 

 two are known to occur in Britain, and in fact only these two are known 

 with certainty to occur north of Central Europe. The genus is hardly 

 known outside the Palsearctic region. 



-'O" 



TaUe of Species. 



1 (2) Legs black, with only the extreme base of the tibise reddish. 



Bristles mostly whitish. 1 rusticus. 



2 (1) Legs considerably reddish. Bristles mostly blackish. 



2 atricapillus. 



1. M. rusticus Meigen. Legs black, with only the extreme base of the 

 tibiae reddish. Strong bristles on the thorax, scutellum, and legs nearly all 

 whitish. 



A large greyish species, resembling JE. rujibarhis and 

 P. alhiceps. 



(J . Dark ashy grey with an admixture of yellowish. Face rather broad, with the 

 ground colour greyish yellow, but dull golden on the bare parts ; facial knob 

 large ; face-beard rather large, but leaving about the upper quarter and the 

 side thirds of the face bare, composed of long bright pale yellow or orange 

 hairs on its lower two-thirds but with the equally long black hairs of the 

 upper thiixl extending down outside the pale hairs to a little beyond the 

 most prominent part of the knob, while a straggling black hair or two may 

 occur still further down ; chin, jowls, and back of the head with abundant 

 long yellow or pale yellow hairs ; a few black bristly hairs (sometimes rather 

 thin) against the upper eye-angle represent the remnants of the usual festoon, 

 and are slightly curved forwards at their tips, and an irregular row of stout 

 bristly hairs extends from them down the back of the eyes, and these bristly 

 hairs are usually inconspicuously yellow but are sometimes black, though all 



