MYRMICA L^EVINODIS. 23 



females, are often seen floating in the air, frequently taking the 

 course of rivers ; thousands of these winged ants may on such 

 occasions be observed floating down the stream. On the hilly 

 fields in Yorkshire I observed a colony of this, or the preceding 

 species, under almost every stone, and amongst one of these 

 colonies I detected a specimen of the rare Batrisus venustus. 



3. Myrmica laevinodis. 



FoBmina. Testaceo-ferruginea, flavido-pilosula ; capite supra, 

 prothorace, scutello, abdominis medio fuscescentibus ; scapo 

 ad basin leviter arcuatim flexo ; metathorace subtransversim 

 striato, spinis binis validiusculis ; nodis petioli sublsevibus. 



Operaria. Testaceo-ferruginea, sparse flavido-pilosula; capite 

 supra abdominisque dorso fuscescentibus ; capite et thorace 

 longitudinaliter striatim rugulosis ; metathorace spinis binis 

 validiusculis ; nodis petioli sublaevibus. 



Mas. Nigro-fuscus, nitidus, flavido-pilosulus ; mandibulis, fla- 

 gellis apice, articulis pedum tarsisque testaceo-pallescentibus ; 

 metathorace inermi, tuberculis utrinque subobsoletis. 



Myrmica laevinodis, Nyl. Adno. Mon. Form. Bor. Eur. 1052. 18 ; 

 Form. Fr. et cUAlger. 78. 2. 



Foerst. Hym. Stud. Form. 64. 35. 

 Curtis, Trans. Linn. Soc. xxi. 213. 2. 

 Smith, Brit. Form. 118. 3. 

 Mayr. Form. Austr. 130. 2. 



Female. Length 2 lines. Pale ferruginous, with the head 

 above, the prothorax slightly, the scutellum more or less, and 

 the middle of the abdomen, fuscous ; the head and thorax 

 coarsely striated longitudinally ; the spines on the metathorax 

 short, stout and acute ; the nodes of the petiole only slightly 

 or indistinctly rugose. 



Worker. Length 2-2^ lines. Only differs from the female in 

 the usual sexual distinctions, 



Male. Length 2 lines. Dark fuscous, shining ; the head sub- 

 opake, obsoletely rugose ; mandibles pale testaceous ; the an- 

 tennae and articulations of the legs pale rufo-testaceous ; the 

 metathorax with obtuse angles, not spined ; wings hyaline. 



This species most closely resembles M. ruginodis. The female 

 has the thoracic spines shorter, and the smooth nodes of the 



