330 THAXTER. — MONOGRAPH OF THE LABOULBENIACE^E. 
in the case of L. eristata which occurs in all the continents; although the members of the large genus 
Pcedenu which it infests, are very varied and numerous. On the other hand certain forms seem to be 
decidedly restricted. L. variabilis, for example, which occurs on a variety of carabid hosts and even on 
.me genus of tiger-beetles, seems certainly not to occur outside the American continents. L. Philonthi, 
tbo, which occurs on members of one of the largest and most widely distributed genera of the Staphylinidre, 
is only found in North and South America. In the two instances last mentioned, enough exotic material 
of the hosts lias been examined to make it reasonably certain that the -species are thus restricted, and 
this is doubtless true of many other forms in connection with which the data are less complete. Among 
still more restricted forms the species on Hawaiian Carabidre may be mentioned, although they are in 
general not confined to special genera; while numberless forms have as yet been seen only on members 
of the same host species, or genus, and from single localities. 
In attempting to arrange the species serially, and at the same time bring together groups of evidently 
related forms, a confusion has resulted in the following enumeration, through the unavoidable juxtaposi- 
tion of unrelated species, and it would have been in some respects less misleading to have adopted an 
alphabetical arrangement. The different groups of species, where groups can be distinguished, center 
about the so-called normal, or flagellata-type . For example the whole series on American Galerifw, 
;iln ly referred to, which comprises about twenty-five species, has apparently come from some type 
nnilar to that of L. Mexicana, which is found widely distributed on the same hosts. The same may be 
true of the group comprising L. Pachytelis, L. Pheropsophi, L. Texana with its varieties, and other related 
forms; some or all of which may have come from L. Darwinii, or a similar type. The series of L. pro- 
liferaru and its varieties, comes also directly from a normal type through the proliferation of cell V; and 
further abnormal divisions in this region result in the type of L. variabilis, wdiich passes directly to the 
types already referred to as seen in the aquatic parasites of Gyrinidse, which themselves vary to forms pos- 
sessing quite normal receptacles. 
In my Monograph I called attention to certain abnormalities which were of interest as showing that 
the sexual characters did not appear to be inherent in any special cells of the receptacle, although the 
primary branches of the subbasal cell are normally antheridial and procarpic respectively. In this way 
perithelia may be wholly or in part replaced by antheridial branches, and, especially in African forms of 
L. proliferous, instances occur in which perithecia may arise secondarily from the subbasal cell, or even 
other cells of the receptacle. 
Laboulbexia fasciculata Peyritsch. 
L. brachiata Thaxter, Proc. Am. Acad. Arts and Sci., Vol. XXIV, p. 11. 
The figures of this species given by Peyritsch give so incorrect an idea of its characters, that I felt no 
hesitation in separating the American form. An examination of European material on the same hosts 
on which it was observed by Peyritsch clearly indicates, however, that the two are identical. Material 
has been examined, from the Florence Collection on Platynus dorsalis Mull., on Pairobw excavatus Payk. 
and on CJUanius vestitus Payk., all of which were Italian ; in the British Museum on Pairobus rufipes 
Fabr., from Britain, No. 638; on Brachinu* sp., China (?) No. 585; the last two differing somewhat in 
color but structurally identical with the North American and European types. Closely allied to L. 
proliferans and resembling especially the varieties divaricate and interposita, it is always separable from 
the fact that the insertion-cell is undifferentiated and is not directly related to the basal cell of the inner 
appendage. En eh basal cell of the appendages, moreover, as we'll as the secondary appendieu I ate cells 
Which result from the proliferation of cell V, bear in the present species more than a single branch or 
appendage; while the basal cells of the latter are relatively large and somewhat inflated, and all the 
lower septa are black and somewhat oblique. The species bears also a certain resemblance to L. varia- 
bilis to which it may be related. 
