No. 2303. RED SPIDERS OF AMERICA— McGREGOR. 653' 



TETRANYCHUS LUDENl Zacher. 



Plate 79, fig. 10. 



Tetranyckus ludeni Zachek, 1910, Mitth. Kaiserl. Biol. Anst. f. Land- und 

 Forst., Heft 9, January. 



A translation of Zacher's (13) text wherein he describes this 

 species is as follows: 



On Salvia splendens, Solumun melmgena, and Cumirbita, St. Cloud, near Paris, 

 April, 1912; Dahlem, 1911 and 1912. This species, concerning which I was able to 

 report on a former occasion, occurred well into the winter in greenhouses. In January, 

 however, the colonies perished, and I was therefore glad when I opportunely, during a 

 visit tc' Paris, again found them in April in the greenhouse of Herr Ian I. I>uden van 

 Heumen . They occurred there in great numbers on Sahio splendens in the greenhouse 

 and also in the forcing beds. Since we jointly studied the species there, and were 

 able to establish its status as a new species, I therefore name the species in honor of my 

 friend. In June I received fi'om Herr Imden van Heumen colonies on SnlviM splen. 

 dens and Cnrcyrhiia which I reared through the entire summer and autumn in the 

 greenhouse, for the observation of which, however, I did not have time. The species 

 appeared spontaneously in great abundance on Solanum melongena in the greenhouse 

 in scattered situations separated by several partitions. The structure of the claws 

 agrees entirely with T. telarius L. The terminal "finger" of the palpus is clearly 

 broader, the lateral "finger" somewhat farther distant from the base of the terminal 

 "finger " than vnXh T. telarius L. The penis [see pi. 79, fig. 10] deviates strongly. It 

 is broader, only slightly curved, not hook-shaped. At the location of the angular 

 projection in other species, there occurs a broad, rectangular projection. In color 

 the species deviates strongly from T. telarius L. and other species, but the young 

 larvae are red colored. It is a large species since the mature female measures 

 0.870 mm. 



TETRANYCHUS FLAVUS Ewing. 



Plate 79, fig. 4. 

 Tetranyckus Jlavus Ewing, 1913, Ann. Ent. Soc. Amer., vol. (j, p. 4-58. 

 The description according to Ewing is as follows : 



General appearance similar to T. borealis Ewing; also similar to T. teloiius Linn., 

 but the individuals are smaller. Color of immature forms green or yellow: of adults 

 green or yellow, with lilack markings not pronounced. Adults are never orange or 

 red. In the winter when deprived of food supply all instare yellow. General struc- 

 tures similar to those of T. telarius Linn., but the tarsal claw in most instances is only 

 five-cleft, the two inner prongs being united. In the case of the female of T. Jlavus 

 the anal spines are situated farther forward than in T. telarius Linn., and also nearer 

 the mai^ins of the genital slit or opening. This species differs from T. horealis Ewing 

 in the tarsal characters which are nearer those of T. telarius Linn., and in having no 

 barb t^ the penis. 



The penis of this species [see pi. 13, fig. 4) is entirely different from the penis of T. 

 telarius Linn. It is long and spine-like. In length it is equal to a third or fourth of 

 the entire length of the body. Inner lobe of penis not prominent, slightly swollen at 

 its anterior end: in size, smaller than the basilar lobe of shaft. Shaft long, curved, 

 and resembling the sting of a wasp; varying greatly in curvature, generally bending 

 downward, then upward, or it may have but a single curve, or it might be straight. 

 Basilar lobe large, subcylindrical, equal to one-fourth of the total length of the entire 

 shaft. Hook and barb alwent. 



