Species of British FormicidcB. 107 



Operana. — Pallide rufo-flavescens, oculis parcissime hirtulis ; 

 pube corporis sericea subtiliori, pilis brevibus erectis sparsis 

 paullo brevioribus, rigidiiisculis. 



Mas. — Fusco-niger, nitidiis ; tenuissime cinerascenti-sericeus et 

 pilosulus ; palpis, antennarum flagellis, pedum articulis tar- 

 sisque testaceo-pallescentibus ; capite satmagno, paululumlatiori 

 thorace; oculis hirtulis ; alis albescenti-hyalinis ; squama petioli 

 subovali apice subangulatim emarginato. 



Formica umbrata, Nyland. Addit. Adno. Mon. Form., p. 1048, 

 17 ; Smith, Append. Cat. Brit. Hyra., 

 p. 116; Foerster, Hym. Stud. Form., p. 

 89, 18. 



Formica brunnea. Smith, Cat. Brit. Hym. p. 2, 4. 



Female. — 3-3| lines. Fusco-testaceous, densely covered with 

 a fine cinereous sericeous pile: head a little wider than the thorax, 

 mandibles rugose, rufo-testaceous ; the antennae, the foce beneath 

 their insertion, and the legs, pale rufo-testaceous ; the eyes thinly 

 covered with short erect hairs ; the head posteriorly deeply 

 concave ; the basal half of the wings brown ; the scale oblong, 

 nearly straight above, the lateral angles rounded, legs stouter and 

 shorter than in F. fiava : abdomen ovate. 



Worker. — Very closely resembling F.Jlava, but is rather larger ; 

 the eyes are pubescent, and the scape stouter. 



Male. — Ig lin. Resembles F. fiava; but the eyes are pu- 

 bescent, the scale emarginate above, and the wings usually clouded 

 at their base ; the basal joint of the flagellum stouter and more 

 globose than in F. fiava. 



This species bears a close resemblance to F. fiava, but is easily 

 distinguished from it, the eyes being pubescent : this cannot be 

 seen unless a high microscopic power be used, then it is visible in 

 all the sexes. The female may be known, if winged, by having 

 the wings brown at their base ; if not winged, the size of the head 

 will distinguish it ; in umbrata it is wider than the thorax, in fiava 

 it is narrower ; the workers are difficult to separate, the head is 

 larger, more shining, and is not covered with a dense pile as in 

 fiava; the scape also is less attenuated at the base and altogether 

 stouter : the ocelli are very distinct. Of the male, I have only 

 seen a single specimen, this has the nervures fuscous, and the 

 wings smoky at their base ; the scale is notched and the eyes pu- 

 bescent. Nylander says the wings are sometimes hyaline, some- 

 times smoky at their base ; and the scale distinctly emarginate. 



1 have frequently found the female of this species on Hampstead 

 Heath, but 1 have not been successful in discovering its Formica- 



