378                       Bionomics of the Ox Warble-Fly

larvae, and when punctured, yield watery disintegrated tissues. What,
however, appeared to be definitely a spineless form of the larva was encoun-
tered by the present writer on two occasions in infected animals at Mukteswar.
This form shows an entire absence of spines except on the anterior and posterior
segments. The cephalopharyngeal skeleton and mouth hooks are morpholo-
gically similar to those of the oesophageal stage larva of H. lineatum. It
differs from the oesophageal larva in being club-shaped instead of torpedo-
shaped, whilst the segmentation is more pronounced and the surface less glossy
(Figs. 1-3). Unfortunately, both specimens were damaged while being
mounted in Berlese's medium.

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                                  Fig. 1.
                     Oesophageal larva. ×11.

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                                  Fig. 2.
                     Spineless larva off back
                             of host. ×11.

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                                  Fig. 3.
                 Cephalopharyngeal skeleton as
                     observed in both types of
                    larvae shown in figs. 1 and 2.