THAXTER. — MONOGRAPH OF THE LAISOVLBIA 1 A< I R. 320 
1 
production of secondary appendages. Similar tendencies toward irregular division of the ap|>enda 's, 
as well as of cell IV and of the insertion -cell, are also seen in L.Clirinali.s (Plate I \l and several allied 
spe<ies, although a perfectly normal type may he associated as in this sp ies, with such abnormalitie 
It is evident that this large genus is a modem one, in which species making is in active progress, 
and it is thus an extremely difficult one to treat from a systematic standpoint; especially in view of the 
limited material usually available for study, and the poor condition in which such material is found in 
collections, on dried insects which have in general been previously naked in alcohol, and it must oftei 
be a matter of opinion whether species, or varieties, or regional variations are in question. In endeavor- 
ing to put in order the almost endless variations of the simpler, or "flageUafa" type, I do not I. I that I 
have in all cases been consistent in my view of what constitutes a variety and what a secies. For exampli 
under L. Texana and L. proliferans certain apparent variations are distinguished by varietal nam. 
while from L. orirntalis I have separated as species, L. japonica, L. pusilla and /.. rlunophora, althottgl 
the differences in these cases are no greater, perhaps, than they an- in ca s where the varietal designation 
has been applied. I do not feel at all sure that it would not have been better to discard varietal designa- 
tions entirely, or at least in L. Texana, L. proliferans and /,. cauliculata, in recognition of the fan that in 
these cases species making is in progress, although the forms do not appear to have become so well defined 
as they are, for example, in a majority of the numerous closely allied species of the remarkable " Uah-rifm* 
group. 
Apart from a crowd of forms which it is very difficult to assemble about any very definite type specie 
there are several subdivisions of the genus which may be distinguished with some definite** and among 
these that which occurs on water beetles belonging to the Gyrinida-, ami which may be grouped abotj 
/,. Gynnhhrum as a type, is perhaps one of the most clearly defined. This group, instead of ... sting 
primitive conditions, which might be expected to throw light on possible aquatic ancestors of tto Family 
as a whole, appears to illustrate, rather, one of its most highly developed types, as is unhealed by tl grea r 
complexity of the receptacle, appendages and, in many cases, of the peritheemm. 'I he more complicated 
members of this group, however, are directly connected with the terr. -.trial types through form like L. 
variabilis; while it contains within itself a certain number of simpler forms like L. roarrtufa, lor example, 
in which the receptacle is absolutely normal. Among these aquatic species, of which there are about 
twenty, L. aquatica alone shows a copious development of typical flask-shaped an.her.d.a. win fe m the 
others no bodies have been observed which can certainly be regarded as organs of tins nature. It should 
be mentioned, however, that material of these forms is almost invariably in bad condition, a. I that I 
have made no attempt to reexamine fresh material of the common forms on American Gynm ... order to 
determine this point. , . ,. , n f 
A somewhat similar and very curious tendency to secondary division, not only m ti* distal cells of 
the receptacle, but in the basal cells of the appendages as well, is also seen m the group »l form rred 
to above, occurring on CJMm and allied carabid genera Schizogeniu,, Umo, etc., although m these ease 
*'- 'endency has not become fixed, as is illustrated in figures 6-6 of Plate LXI. 
A, might be expected in a genus which includes more than two hundred s,, ies the paras.t.s.n of 
beell 
the 
the hitter is unusually varied; and althou^ 
forms are known to 'occur on Staphylinid*, Cyrhmhe, Cicindelid*, and several other orders among 
Coleoptera; on Diopsida, among the flies; on Termites among the Neuroptera; on two <--'; - 
and even on ants. It is rather remarkable that such extreme differences m host, have . most ,.a 
type 
f the 
inuuceu no cousuiciauic urpi iuh. .1^. ~~ .» ' . , X t . ... .,,,,1 Hcmenon- 
host is so unusual as in those of L. [Iagci and L. Fon„kan, m wh.,1, ..ocuron Neun,,,,-ra ^ 
.... ... ^ - 1 ,r :ns* M A I STnnnhxmvft are aberrant, it is hardl y possibft 
tern. Whether the forms on 
to determine from the published figu 
peeies 
TU distribution of the species corresponds in son,.- butane* U. that of the nus „f be- ins, K as 
