Bfitish Sjjecies o/HalipIus. 99 



flirough the kindness of several entomolonrists. Captain Sainle 

 Clause Deville of Paris, Dr. Everts of ^s Gravenliaoe, and the 

 late Herr Ganglbauer of Vienna. Ilerr Reitter of Paskaii 

 and Herr Schulz of Hamburg have also supplied me with 

 specimens which have been useful. 



It is after working through all this material that I have 

 come to the conclusion that tlie only entirely reliable character 

 tor separating the seven species of the group is the form of 

 the ^deagus, and that, although the other characters referred 

 to are usetul in allocating an individual to a particular species 

 they not infrequently contradict one another, so that iii some 

 cases it 13 extremely difficult to come to a decision at all in 

 the case of the females. 



Apparently these characters and others which I find even 

 . less useful are not universally variable, as Roberts (r6) for 

 instance who has written a long paper on North American 

 Haliphds, says that '^ the structural characters most useful in 

 separating the species are the form and markings, such as 

 depressions, margins, &c., of the prosternal process, meta- 

 sternum and coxal plates, as well as the shape and structure 

 of the parts of the upper surface of the body,^^ and he further 

 lays stress upon the value of maculation, but this speciallv 

 applies to the genus Peltodytes, as he mentions that in IlaU- 

 phis variation in colour-markings is not at all uncommon 



I will now discuss the value of the chief characters which 

 have been used in separating the species. 



General Foem. 

 A character upon which Edwards lays some stress is the 

 general form ot the insect, and this involves the shape of the 

 thorax and the outline of the elytra. Now there is no doubt 

 that the general form is decidedly useful as a guide in 

 separating the species, although the differences are more 

 apparent than real, but it is usually possible to allocate 

 individuals to one of two categories as laid down bv that 

 author. -'^ 



H. ritficoUis, hetjdeni, and most nomax have the thorax 

 apparently more than twice as broad as long and with the 

 sides strongly convergent in front and tlie elytra are usually 

 evidently widest before the middle. //. apicalis, fluviatilis 

 nomox yar. hroiojieanus, wehncM, and immaculatus usually 

 have a thorax which appears longer in proportion to its width 

 with the sides less strongly convergent in front, while the 

 eljtra are usually widest in the middle, except in the case 

 ot v^x.hrowneanus which is a member of the other group as 

 to this last character. 



7* 



