175 



NOTES ON ACARI. 



With Plate 10. 



BY 



Dr. A. C. OVDEMAKS. 



[Hoplophora] magna Nicolet. 



H. Nicolet mentions this species as being 1.46 millimeters in 

 length (Arch. Mus. Paris , VII , p. 472). I found specimens of 

 4.5 millimeters, but also of 1.25, 1.2, 1,125, 1.1, 1.0, 0.9 and 

 of 0.5, nay even of 2.0 millimeters. Have we here as many species , 

 or are these different measurements the result of different influences ? 

 I have not been able to observe any other differences in the spec- 

 imens but their lengths. 



Oppia confervae Schrank. 



Frangiscus de Paula Schrank gives in his Enumeratio Insectorum 

 Austriae indigenorum, 1781, sub n° 1054, the following descrip- 

 tion of an Acarus found by him under water and amongst the 

 threads of Confervaceae : 



«,1054. C4ONFERVAE, Gonfervenmilbe ». 



« Acarus fuscus ovatus , pedum geniculo secundo minimo , tertio 

 Seta longa armato » . 



(kBescr. Minimus, vix nisi ope lentis visibilis; fuscus; pedibus 

 pallidioribiis. Figura globosa, antico acuminata. Pedes aequalis 

 longitudinis & structurae. Si bases pedum non computes , articulis 

 constant quinque; primus, tertius, quartus teretes, in apice tertii 



