The development of contemporary microscopic techniques is due to the long-term improvement of optical devices - various laser types and microscopic objectives in first place. Nowadays, advanced microscopic techniques, which give us various and compatible information, enable complete characterization of some microscopic objects. Nonlinear microscopy, by the detection of nonlinear effects during femtosecond laser beam scanning, provides information on oriented structures, refractive index changes or fluorescent properties from the bulk. Nonlinear effects, multi-photon absorption, second and third harmonic generation are generated only in the laser beam focus where sufficiently high intensity is obtained by objectives of high numerical aperture and ultra-short laser pulses. In this way it is possible, in optical sense, to "cut" the sample to very thin slices in order to get the 3D image of the micro-object by the utilization of special computer programs. After the development and setting up the instrument, the first results in the Photonics Center of the Institute of Physics are obtained on the samples of endemic insects Pheggomisetes ninae and Plussiocampa christiani, which inhabit the caves of south-eastern Serbia and central Balkans, as well as on composite eyes of cabbage white butterfly (Pieris rapae) and some endemic spieces of butterflies (Lepidoptera).