July, 1899.1 M9 



NOTES ON CERTAIN PALJEARCTIC SPECIES OP THE OENUS 

 HEMEROBIUS. 



No. 3—^. STIGMA {LIMBATUS), AND THE GROUP OP E. PINL 



Br ROBERT McLACHLAN, F.R.S., &c. 



The species here considered are apparently exclusively attached 

 to Conifers, the inference being that these trees furnish forms of the 

 lower Rhynchota on which the larvae feed. 



They form an exceedingly puzzling assemblage. Tn the first 

 species (stigma) there are certain characters that will enable it to be 

 separated, even by the ^ appendages (though these are formed quite 

 after the same plan), and it is one of the least variable in the whole 

 genus. 



But in treating of the "group" of pini one is almost driven 

 to despair. Neither my excellent fellow-worker Mr. Morton, nor 

 myself, has been able to discover any tangible ($ characters (and from 

 this cause figures are given for only one " species"). Mr. Morton 

 has gone to the trouble of making many figures ; these show slight 

 variation in the depth and form of the excision between the branches 

 of the fork of the appendages, but upon analysis these slight differ- 

 ences are not correlated with characters in the markings, &c., that 

 appear to be specific, and are probably due to alterations in drying. 

 On the other hand three species appear to exist on general characters. 

 Considered from the J characters only, we are apparently dealing with 

 one protean species, and my coadjutor Mr. Morton, perhaps with reason, 

 is of opinion that this is so ; he thinks there are individuals that 

 show transition states in the general characters : in this case there 

 would be one species ("pini^' by right of priority) divided into three 

 " races." I have wavered in deciding upon a course to adopt, and have 

 ended by accepting three "species" provisionally, dependent upon 

 more exact examination of living materials. If nothing tangible be 

 discovered we may, I think, look upon all three as one species, for it 

 appears to me scarcely possible that the all-important (^ characters 

 should fail in their value. 



Dr. 0. M. Eeuter (" Neuroptera Fennica," 1894) discovered a 

 very useful neural character whereby to separate stigma from the piiii 

 group. I use it in the table given below : — 

 Thorax unicolorous. A small transverse nervule (very rarely absent) placed between 



the radius and the upper cubitus close to the base of the wing H. stigma. 



Thorax with a more or less distinct pale median band. A strong transverse nervule 



(very rarely absent) between the origin (or nearly so) of the first sector of the 



radius and the u^^ev cxxhiins, distant from the haseoit\\ii wing...H. PINI, &c. 



