A. C. OUDEMANS, NOTES ON ACARI. 71 



XVII. Linobiinae. 



One genus only 1 Linohia Beri. 



XVIII. Hemisarcocoptinae. 



One genus only 1 Hemisarcocoptes Lign. 



5. On parthenogenis or agamic reproduction 

 in Acari. 



The purpose of this little essay is to draw my readers' 

 attention to the literature on the subject, to point out with 

 justness what has hitherto been done with scrupulous and 

 zealous study to settle the question, and finally to warn for 

 hazardous hypothesizing. 



In the Annales des Sciences naturelles, 1 834, 

 sér. 2, V. 2. p. 104, Duoiis describes a fourlegged mite, which 

 he supposes to be the larva of Tetrany chus [corv. Tetronychus); 

 he based his supposition partly on the similarity of the mouth- 

 parts and legs, partly on the »habitat« common to both. He 

 examined especially the mites on Salix and Tilia. 



Though already Dujardin (Annales des Sciences 

 naturelles, 1851, sér. 3, v, 15, p. 166) asserted that he 

 distinctly saw eggs in the »larva«, and therefore uttered his 

 firm belief that we have here to do with an adult though 

 four-legged mite, which he calls Phytoptus (corr. Phytocoptes), 

 and which is not in the least related to Tetronychus. 



Scheuten, 1857, (Arch. f. N a t u r g. v. 23, p. 104— 112) 

 again defended the idea of Duoks. He examined the mites of 

 Pirus communis. He, however, falls in a new ambuscade by the 

 presence of quite another mite which he calls Typldodromus pyri 

 and thinks it is the adult of the »larvae«. (His drawing of the 

 adult mite betra3's at once Seiulns vepallidus (C. L. Koch), a 



