HANSEN AND SÖRENSEN, THE TARTARIDES. 35 



of these had been secured together with females or immature 

 specimens belonging to the same species, while of the eighth 

 form the males had been captured at a distance of at least 

 twenty (EngHsh) miles from the spöt where a female certairJy 

 belonging to the same species was found. The major part of 

 the characters used by me vary according to the age (and 

 sex) of the animals; when the animals are only half-grown 

 or still y ounge r most of the parts serviceable for producing 

 a good description of the form differ so much from those in 

 the adults that is it impossible to establish recognisable spe- 

 cies on such specimens ^ An author who has only a small 

 material of this tribe ought not as a rule to establish a spe- 

 cies, when he is not sure of that at least one of the speci- 

 mens is adult. 



It is probably superfluous to discuss the characters used 

 in the foUowing descriptions : in the ncxt paragraph (on the 

 measurements, etc.) the information necessary for the under- 

 standing of several characters is given. But some remarks on 

 specific differences not used in my descriptions may be pro 

 duced. The front part of the head differs somewhat in shape 

 in various species (compare Pl. 3., fig. 1 a with Pl. 4., fig. 3 a), 

 but it would have been necessary to figure this part of each 

 species. as the differences are often small or very small and 

 impossible to elucidate by a description, but I deemed it su- 

 perfluous to draw so many figures in order to arrive at a 

 meagre result. — The triangulär plates of the first thoracic 

 tergite are more or less narrow — or rather more or less short 

 — but that portion of the thorax is often contracted or folded 

 so that it is next to impossible to observe the real shape of 

 these plates without damaging the animal. — The trochan- 

 terial part of the palps has always a conical acute process on 

 its inner surface, and the position of this process — its distance 

 from the lower and from the anterior margin — differs in 

 various species, but I gave it up as a character, because it is 

 sometimes impossible to use without a difficult examination. 

 The coxse of the second pair of legs vary a little as to the 

 proportion between their length and breadth, but the diffe- 

 rence is small and therefore omitted. Several minor differences 

 not mentioned in the text may be observed on the dramngs. 



^ Foi' this reason I have omitted three such very young specimens 

 from various eountries, though at least two of them belonged to species 

 otherwise unknown to me. 



