Tylobolus fredricksoni (Causey 1955)

Tylobolus fredricksoni (Causey)
? Spirobolus uncigerus, Cragin, Washburn Lab. Nat. Hist. Bull., vol. 1, no. 4,
p. 145. 1885. ? Spirobolus uncigerus, Kenyon, Proc. Nebraska Acad. Sci., vol. 3, p. 16. 1893. ? Tylobolus uncigerus, Gunthorp, Kansas Univ. Sci. Bull., vol. 7, p. 164. 1913. ? Tylobolus uncigerus, Gunthorp, Canadian Ent., vol. 53, p. 88. 1921. Californibolus fredricksoni Causey, Journ. Kansas Ent. Soc, vol. 28, p. 78, figs.
Ic, 4, 5. 1955. Californibolus fredricksoni, Chamberlin and Hoffman, U. S. Nat. Mus. Bull., no.
212, p. 161. 1958.
Diagnosis. — It is my opinion that the holotype of this species is a subadult. I cannot check segments, how^ever, because the vial labelled " holotype " contains fragments of the anterior end of a small specimen and of the posterior end of a larger one. The gonopods resemble those of immature specimens of related species and it is impossible for me to give any indication of their characteristics in the adult. The species certainly differs from uncigerus in having few striae on the sides. The weaker development of the inner plate of the tibiotarsal region of the posterior gonopods may prove to hold in the adult as a character for separating this from utahensis. The true status of the species must await discovery of an adult.
Description. — Based on the type specimen (specimens?). W of smaller anterior portion 4.7 mm., of larger posterior portion 6.1 mm. The anterior portion consists of fragments including the head, first 10 segments, and 11 other segments. The posterior portion consists of 27 segments including the telson and anal valves. The total number of segments is thus 48 (Causey's count of 58 must have been a typographical error ; no specimens of the subfamily that I have examined have had that many segments).
Eyes 33 +33. Clypeal setae 6, labral setae 14. Most stipital setae are missing but apparently there were about 6 per stipes.
Striae of hindbelts ending about midway between pleural sutures and repugnatorial pores.
Anal lips indistinct.
Coxae and other podomeres in general resembling the usual form for the genus ; some pregenital coxae still retaining the ventral setae always present in immatures. Claws of 1st legs as long as last podomeres; other claws missing.
Coxal endites of anterior gonopods much exceeding apex of sternum, their mesoventral corners only slightly produced ventrad. Anterior telopodites apparently not uncinate distally although this character not certain for adults. Posterior telopodites short, simple, no prominent division between prefemoral and tibiotarsal portions; distal process very short (may be longer in adult) ; margins of opening of seminal receptacle slightly serrate, this perhaps a diagnostic character.
Type. — Male (SMUK). Locality: Douglas, Kansas. The type material was collected Sept. 1, 1949 by R. W. Fredrickson. No further specimens have been taken.
Tylobtflus species? Figure 223