A Reinterpretation of the Larval Maxilla of the Blepharoceridae (Diptera, Nematocera)
D. A. Craig,
By
Zoology Department, University of Canterbury,
[Received by the Editor, 24 February 1966 .]
Abstract
The larval maxilla of Blepharoceridae is reinterpreted on evidence from the embryology of Neocurupim chiltoni and the maxillary musculature of larval N. chiltoni, N. hudsoni and Hapalothrix lugubris.
In the current interpretation of the larval maxilla of the Blepharoceridae (Muller, 1879 and Bischoff, 1928) as exemplified by Hapalothrix lugubris Leow (Fig. 1), the anterior lobe is termed the “ Maxillarlade ” {=. lacinia), the median sensory lobe the “ Maxillartaster ” (= maxillary palp) and the posterior hookcovered lobe the “ Mentallappen (Bolster) ” or “ Almofadas ” (= “little cushion”).
During the embryonic development of Anurida maritima (Collembola: Imms, 1906); Baetis vagans (Ephemeroptera: Needham, 1935); Lepisma saccharina (Thysanura: Johannsen and Butt, 1941) ; and Neophylax connicinnus (Trichoptera: Patten, 1884) and Calandra oryzae (Goloeptera: Teigs and Murray, 1938), the maxillary segments develop basal and distal lobe-like portions. The distal portion grows posteriorly but then rotates to become anteriorly orientated and forms the maxillary palp.
The embryonic maxillary segments of Neocurupira chiltoni also develop basal and distal lobe-like portions and by the sixteenth day the distal portion (Fig. 2 Mxp) covers the lateral margin of the labial segment and a small portion of the prothoracic segment, but in this case does not rotate to form a typical maxillary palp. Rather the distal portion forms the “ Mentallappen (Polster) ” and the basal portion grows forward to form the “ Maxillarlade ” and “ Maxillartaster ”.
Even though the distal lobe of the maxilla of N. chiltoni does not rotate and does not form a typical maxillary palp, because the initial embryonic development of the maxilla follows so closely that of the other orders of insects, it is postulated that the “Mentallappen (Polster)” and not the “Maxillartaster” is the true maxillary palp.
This hypothesis is supported by the musculature of the larval maxilla. According to Das (1937) and Hinton (1958), dipterous larvae never have muscular insertions on the maxillary palp. Das further states that, though certain muscles may be lost in the larval maxilla, the cranial flexor muscle of the lacinia is always retained. Examination of the musculature of the maxilla of larval Neocurupira
chiltoni, N. hudsoni Lamb and Hapalothrix luguhris Leow, shows that the sensory lobe previously interpreted as the maxillary palp is the only maxillary structure to have a muscular insertion. Therefore it is concluded from the criteria of Das and Hinton, that the sensory lobe is the lacinia and not the maxillary palp. The remaining part of the maxilla, the anterior brush-like region previously interpreted as the “ Maxillarlade ” or lacinia is probably the galea. However, a study of the complex maxillary sclerites might clarify this point. Figure 3 presents the new interpretation of the larval maxilla of the Blepharoceridae.
Literature Cited
Bischoff, W. C. M., 1928. Die Okologie der palaarctischen Blepharoceriden. Ergebn. Fortschr. ZooL, 7: 209—278. Das, G. M., 1937. The Musculature of Mouthparts of Insect Larvae. Q. Jl. Micr. Sci., 80: 39-80. Hinton, H. E., 1958. The Phylogeny of the Panorpoid Orders. A. Rev. Ent., 3: 181-206. Imms, A. D., 1906. Anurida. L.M.B.C. Mem. typ. Br. mar. PI. Anim., 13: 1-99. Johannsen, O. A., and Butt, F. H., 1941. Embryology of Insects and Myriapods. McGrawHill Book Company. 462 pp.
Muller, F., 1879. A Metamorphose de um Insecto Deptero. Archos. Mus. nac. Rio. de /., 4: 49-85. Needham, J. G., 1935. The Biology of Mayflies. Comstock Publishing Company. 759 pp. Patten, W., 1884. The development of phyganids (Trichoptera), with a preliminary note on Blatta germanica. Q. Jl. Micr. Sci., 24: 549—602. Tiegs, O. W., and Murray, F., 1938. The embryonic development of Calandra oryzae. Q. Jl. Micr. Sci., 80: 159-284.
D. A. Craig, Department of Entomology, The University of Alberta, Edmonton, Canada.
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