06 pfiAR. 



of this paper, by which the observer will see the cylindrical form, also 

 the position of the bristles and the clearly-defined form of the legs, 

 showing the distinct joints, and the characteristic subterminal feather- 

 formed holding-claw (Haftklaue, Landois).* 



For distinction of species, such characteristics as the form, and 

 comparative length and breadth of body ; form of thoracic shield ; 

 form, direction, and length of proboscis ; cliaracteristics of legs, and 

 nmnber of branches of the feather-claw; length, &c., of bristles, and 

 length and breadth of developed males and females ; are some of the 

 points given. Very much more besides is clearly entered on, as for 

 instance the change in form of the male of the Nut Plu/toptus {P. avel- 

 lance) at the time of sexual development, and the apparatus of repi'O- 

 duction is especially entered on, with measures and descriptions ; the 

 form of the egg is also given where known. Synonyms, or what 

 might be synonyms if the names referred to had been accompanied by 

 full description, are given; but as it is pointed out, names without 

 full descriptions accompanying are unserviceable. In fact, " bare 

 words" are, as was well said by Dr. Amerling, "of only temporary 

 use as a means of reference, pending fuller description." 



In the following pages I give (with permission) some abridged 

 ■technical descriptions ; bat as it is hardly just and fair to the author 

 of a work of such depth of research to place mere fragments of it before 

 .scientific readers, in translation and in abridged form, I append to the 

 account of the Plum-leaf Phytoptvs a copy in full of Dr. Nalepa's descrip- 

 tion, as an example of his careful and thorough method of dealing with 

 his subject. Also I should be to blame if I did not tender my especial 

 and hearty thanks for the kindness with which he aided me by his 

 clear instructions in this difficult study. 



Pear-leaf Blister-galls [Phytoptus pyri, Nalepa). — "Body cylin- 

 drical, about 5-6 times as long as broad. Thoracic shield very small, 

 semicircular." ..." The proboscis is strong, slightly curved, directed 

 forward, and 0-025 mm. long. The legs are rather weak and short, 

 but distinctly jointed. The bristles are very fine and short. The 

 holding-claw (' Haftklaue ') is very small, exceedingly slender, and 

 four-branched." (This is sometimes described as a " feather-bristle " ; 

 see figs, of terminal four-branched claw, p. 84. — E. A. 0.) . . . . " The 

 abdomen is uniformly ringed (about eighty rings), and rather finely 



punctate." " The above-named species produces on the leaves 



of the Pinis communis, L., numerous pustule-formed swellings, some- 

 -what raised on both sides of the leaf, smooth, at first green, afterwards 



* For full description of Phytopti, — male, female, and eggs,- — see ' Beitrage z. 

 Syst. d. Phyt., in : Sitzgsb. d Kais. Akad. d Wiss. in Wien,' 1889. Bd. 981 (separate 

 impression), pp. 8—10. 



